attachment #2. technical specification for electrical

Attachment #2

Technical Specification for Electrical

Al-Ammara Gas Turbines Power Plant Project

Revision 0, March 4, 2013 of 71 Issued for Bids

Al-Ammara

Gas Turbines Power Plant Project

ELECTRICAL

REV. Date Prepared by position signature Reviewed by position Signature

REV.1 Basheer Hatem Rahman Jaber Kaadhem Joda Salah Mahdi Rafea Mussa Abed Allah Alek Saad Fraih Uroba Soad

Mech.Eng I & C Eng Elect. Eng. Civil Eng. Elect.Eng. Elect.Eng. Chemical Eng. Chemical Eng.

Majid Hantoosh Raad qasim

Director general Director assistant/Commercial manager

REV. Date Approved by Position Signature

REV.1 Salam Kazaz Deputy Minster



Table of Contents

7 ELECTRICAL ........................................................................................................................................... 5

7.1 Detailed Scope of Work .................................................................................................................... 5

7.1.1 General ...................................................................................................................................... 5

7.1.2 Detailed Scope of Work ............................................................................................................ 5

7.1.3 GE Equipment ........................................................................................................................... 6

7.2 Isolated Phase Busduct ...................................................................................................................... 6

7.3 Transformers ...................................................................................................................................... 7

7.3.1 General ...................................................................................................................................... 7

7.3.2 Oil filled transformers ............................................................................................................... 7

7.3.3 Unit Auxiliary Transformers ..................................................................................................... 8

7.4 Switchgear ......................................................................................................................................... 9

7.4.1 General ...................................................................................................................................... 9

7.4.2 MV Switchgear .......................................................................................................................... 9

7.4.3 LV common site switchgear, LV and DC switchgear ............................................................. 16

7.4.4 LV and DC Switchgear ............................................................................................................ 23

7.4.5 Diesel Generator LV/MCC Panel ............................................................................................ 27

7.5 Current transformers ........................................................................................................................ 27

7.6 Voltage transformers ....................................................................................................................... 28

7.7 DC supplies system ......................................................................................................................... 28

7.8 Uninterruptible power supply equipment ........................................................................................ 29

7.9 Protection ......................................................................................................................................... 29

7.9.1 General .................................................................................................................................... 29

7.9.2 Transformer protection ............................................................................................................ 31

7.9.3 Medium and high voltage motor protection relay ................................................................... 33

7.9.4 Feeder Protection ..................................................................................................................... 35

7.9.5 Low impedance busbar protection system ............................................................................... 36

7.9.6 Black start diesel generator and emergency diesel generator protection ................................. 39

7.10 Diesel Generator Set Synchronizing ................................................................................................ 40

7.11 Black start diesel generator .............................................................................................................. 40



7.11.1 Starting System ........................................................................................................................ 41

7.11.2 Generator Local Control Panel ................................................................................................ 42

7.12 Emergency Diesel Generator ........................................................................................................... 43

7.13 Tariff Metering ................................................................................................................................ 43

7.14 Motors for Pumps and Electrically Operated Valves ...................................................................... 43

7.15 Earthing ........................................................................................................................................... 43

7.16 Cabling ............................................................................................................................................ 44

7.16.1 General .................................................................................................................................... 44

7.16.2 Medium voltage cables ............................................................................................................ 46

7.16.3 Low voltage cables .................................................................................................................. 46

7.16.4 Control and instrumentation cables ......................................................................................... 46

7.16.5 Telephone cables ..................................................................................................................... 46

7.16.6 Optical fiber cables .................................................................................................................. 46

7.16.7 High temperature cables .......................................................................................................... 47

7.16.8 Intrinsically safe cables ........................................................................................................... 47

7.16.9 Cable installation ..................................................................................................................... 47

7.16.10 Electrical equipment for hazardous areas ............................................................................ 49

7.17 Electrical “building services” .......................................................................................................... 49

7.17.1 Scope of works ........................................................................................................................ 49

7.17.2 Normal, external and emergency Lighting systems ................................................................. 50

7.17.3 Small power installation .......................................................................................................... 59

7.17.4 Distribution system .................................................................................................................. 61

7.17.5 Cables and wiring .................................................................................................................... 63

7.17.6 Lightning protection system .................................................................................................... 64

ANNEX 1: Generator Step-Up Transformers



7 ELECTRICAL

7.1 Detailed Scope of Work

7.1.1 General This part of the specification details the requirements for the electrical plant and all associated auxiliary equipment, and the criteria against which the equipment shall be designed.

The electrical system shall be designed generally on a unitized basis, the only possible interconnections being at medium and low voltage levels where an essential supplies/common board may service more than one unit. The black start facility shall be connected to the power block electrical systems via the medium voltage switchgear system.

The Contractor shall conduct electrical short circuit study for the entire system that shall be used to size the electrical equipment at different voltage levels in the plant. The contractor shall perform and submit documents for System Design Basis, Load Flow Study, Insulation Coordination Study, Earthing System Design, taking in to consideration MOE’s general specifications. The scope of supply of electrical equipment is covered in Chapter 3 of these specifications.

The Contractor shall supply and install all the electrical equipment and the electrical interconnections needed in the power plant except the material supplied by GE but shall provide all the electrical interconnections including those between GE supplied equipment (including cable accessories such as trays, cable glands and any other accessories required for complete installation by the contractor). The Contractor’s scope of supply shall include, but it will be not limited to the lists included in the next paragraphs.

7.1.2 Detailed Scope of Work The following equipment / system shall be designed, furnished and installed by the Contractor:

a. Isolated phase busbars (bus duct systems) between Generator Circuit Breaker (GCB), Generator step up transformer and Unit auxiliary transformer.

b. MV Switchgear

c. LV Common Site Board

d. Unit Auxiliary Transformers

e. Site Auxiliary Transformers

f. LV switchgear

g. DC switchgear

h. MCC (except GT MCC supplied by GE)



i. MV cables

j. LV cables(including high temperature and fire proof cables)

k. Control and measure cables (including high temperature and fire proof cables)

l. Telecommunication cables

m. DC supply system (except DC system used for GT control in GE scope, located in GE PEECC)

n. UPS (except UPS system used for GT control in GE scope, located in GE PEECC)

o. Protections relays for all electrical equipment, metering, monitoring, supervision, control, alarm systems for all equipment in contractor’s scope

p. 1 (one) black start diesel generating set at 6.6kV

q. 1 (one) emergency diesel generating sets at 0.4 kV

r. Motors for pumps and electrical operated valves

s. Plant and equipment earthing system

t. Electrical equipment rated for hazardous area, where required

u. Normal and emergency lighting and socket system.

v. Lightning protection system.

w. Cathodic protection system.

x. Cable raceway system including trays and conduits (above ground and underground)

y. Interface with existing system, other contractors

z. Any equipment, material and commodities not specifically mentioned but required for satisfactory operation of the overall plant.

7.1.3 GE Equipment The equipment /system that are furnished by GE and to be installed by the Contractor are listed in Chapter 3 of these specifications.

7.2 Isolated Phase Busduct Equipment shall be provided with VTs, CTs, and disconnect switches where necessary. The connections shall be designed to withstand currents under worst possible short circuit fault conditions. Neutral



connections shall be designed for full phase to earth voltage, and shall be adequately rated to take the full unrestricted fault current for three seconds.

The busbar installations shall comply with IEC 60071, IEC 60105, and IEC 60298.

Induced currents in adjacent structures shall be kept to a minimum.

A means of preventing electrolytic corrosion shall be provided where the conductor is connected to a dissimilar metal.

The enclosures shall be completely weatherproof. Flexible connections shall be used to connect the busbar to generator circuit breakers and transformers. Dry filtered air shall be used to pressurize the bus duct, with an alarm to the plant control system for high and low pressure.

Earthing of the busbars shall comply with IEEE 665.

Cubicles which form part of the IPB system shall be complete with anti-condensation heaters.

7.3 Transformers

7.3.1 General The following requirements apply to the transformers included in Contractor’s scope of work. All three phase transformers shall be oil filled type with copper conductor winding . For more requirements on the Generator Step Up (GSU) refer to Annex 1 at the end of this Chapter 7.

7.3.2 Oil filled transformers All three phase transformers shall be of core or shell type construction. All transformers shall be complete with all accessories and necessary auxiliary equipment. All transformers shall comply, and be rated in accordance with IEC 60076.

All transformers shall be capable of operating continuously without damage between 47.5 Hz and 52 Hz.

The maximum hot spot temperature rise of the transformer winding, under all site and operational conditions, shall be 68°C. .

Oil filled transformers shall be fitted with lockable drain valves to enable all oil filled compartments to be drained, and adapters shall be provided for connection to oil filtration plant. Sampling devices shall also be fitted independently of the drain valves. It shall not be possible for the oil in the sealing end chambers to mix with that of the main tank.

First filling of oil shall be provided for each oil filled transformer. The grade of oil shall comply with the requirements of IEC 60296. Oil filtration equipment shall be provided for the largest transformer.

Silica gel breathers shall not use cobalt chloride.



Pressure relief devices shall be provided for each oil filled compartment. These devices shall discharge oil at ground level. Alarms shall be repeated to the plant control system.

Safe access shall be provided to transformer conservators and Buchholz relay. This shall take the form of an access ladder with hoops.

Radiators, are connected directly to the tank and shall be detachable. All oil filled transformers shall be fitted with an oil temperature indicator that can be manually reset. Alarm and trip facilities shall also be provided.

Marshalling kiosks for oil filled transformers shall be complete with temperature indicators, test facilities, interposing relays for supervisory control, control and protection for cooling plant with an auto-manual changeover switch. Each generator transformer kiosk shall include a single phase and a three phase socket. The Marshalling kiosk rating shall comply with IP 55.

Sealing end chambers shall be oil filled, and be provided with removable covers. The chambers shall accept the cable sealing ends, and provide testing facilities for the cable. The main conservator tank shall maintain the oil level in the sealing end chambers.

Bushings that house current transformers shall be arranged so that they can be removed without disturbing the current transformers, secondary terminals, connections or pipework.

The construction and mounting of all bushings shall ensure that, in the event of flashover, current has a definite path around joints fitted with gaskets. On capacitor type bushings a tapping shall be brought out to a separate terminal for power factor testing at site. The terminal shall be earthed when the weatherproof cover is in position. Stress shields shall be regarded as part of the bushing assembly.

Internal connections to transformer bushings shall be flexible.

On line condition monitoring equipment shall be fitted to transformers with ratings greater than 20 MVA.

The terminal arrangement and connections shall not restrict access for maintenance and inspection.

All windings below 72.5 kV shall be fully insulated.

The transformers equipped with off load tap changer shall include provisions for padlocking and tripping in the event of inadvertent operation of the tap changer while transformer is energized.

7.3.3 Unit Auxiliary Transformers Unit auxiliary transformers shall comply with all the prescription foreseen for oil filled transformers.

Unit auxiliary transformer shall be designed to feed both generation unit auxiliaries (in the worst conditions) plus all stations common loads.

Unit auxiliary transformer shall have ONAN cooling.



The HV terminals of the Unit Auxiliary Transformers shall be arranged for connection of isolated phase busbars.

Cable boxes shall be suitable for the connection of XLPE or EPR insulated cables. The body of the cable box shall be provided with an earthing bolt or stud. Cable boxes shall be air insulated and IP 65 Phase segregated cable boxes shall be used for single core cables. The type of cable boxes (open or bottom, cables exact route, etc) shall be finalized during the design phase and shall comply with the applicable IPC requirements.

7.4 Switchgear

7.4.1 General All the ancillary equipment, within of each switchgear, shall comply with IEC 60947

All the switchgears must be of metal clad type with three isolated compartments.

The overall height of switchboards shall not exceed 2.5 m.

All switchgear shall be accessible for maintenance without the need for extensive removal of internal equipment.

Indoor equipment shall have a degree of protection to IP41, outdoor equipment shall be IP55.

It shall not be possible to accidentally access live parts of the equipment. The switchgear shall be vacuum or SF6 type, and comply with the IEC standards. .

Control sections and cable compartments shall be provided with internal lighting. Each LV switchboard shall be complete with a control circuit transformer. The primary winding and the non earthed pole of the secondary winding shall be connected through a fuse.

Internal wiring shall be run in low smoke and fume (LSF) cable trunking. No more than two wires shall be connected to one terminal. Wires shall be identified at each end. Wiring above 50 V, or wiring connected to pilot cables shall be segregated from other wiring.

Terminal blocks shall be stud or insertion type. Spare terminals shall be provided. All terminal blocks shall be labelled with a unique identification reference.

All indicating instruments shall be in accordance with IEC 60051 Class 1.0. Motor ammeters shall be capable of withstanding motor starting currents. Voltage operated instruments shall be protected by a fuse.

7.4.2 MV Switchgear .

7.4.2.1 General Medium Voltage switchgear shall be metal clad dead front type. It shall be normally controlled from the plant Distributed Control System (DCS).



The following are the major requirements for the MV switchgear, which shall be GE or equivalent.

7.4.2.2 Product configuration summary The Indoor circuit breakers shall be designed for applications on 6,6 kV power .It shall comply with IEC 62271 standard, with maximum short circuit breaking capacity of 40kA. The circuit breaker shall be designed to be used with 6,6 kV rated switchgear, in accordance with IEC 62271-200.

The 6,6kVcircuit breakers shall be available in “Withdrawable” version and shall be designed for use in indoor applications only. Minimum ingress protection shall be IP4X for external housing and IP2X for inside compartment.

The equipment ratings shall be valid under the following ambient conditions:

a. Minimum ambient temperature : – 5 °C

b. Maximum ambient temperature: + 55 °C

c. Maximum relative humidity: 95 %

d. Maximum altitude: 1000 m above sea level).

7.4.2.3 Applicable documents International Standards - The Switchgear and its components shall comply with the following IEC Standards:

a. Circuit breakers:62271-100：2006

b. Switchgear - 62271-200：2003

c. Earthing switches - 62271-102 : 2001

7.4.2.4 Required Product Features Indoors 6,6 kV circuit breaker shall be compliant to standards IEC 62271 -100: 2006. The circuit breaker can be applied as an incoming breaker, feeder breaker, tie breaker, with ratings as per the following Table1 (VCB Rating):.

ITEM Circuit breaker

Rated Voltage: 6,6kV

Rated Current 630/1250A

Rated Frequency 50Hz

Rated power Freq withstand voltage (1 min): 20 kV

Saleem

Highlight



ITEM Circuit breaker

Rated lightening impulse withstand voltage: 40 kV

Rated short-circuit breaking current: 31.5 kA

Percentage of DC component 40%

Rated short-circuit closing current: Ipeak 100 kA

Rated short time withstand current: 31.5 kA

Rated peak value withstand current: 100 kA

Rated duration time for short-circuit 3 Sec

Opening Time <40 msec

Closing Time <55 msec

Operation sequence O-0.3s-CO-180s-CO

Mechanical life operations: M2-20000

Electrical Endurance Capability class E2

Capacitor bank Switching current 400A

7.4.2.5 Mechanism Circuit breaker shall incorporate a stored energy mechanism. The key features of the mechanism shall be:

a. The spring can be charged either manually with handle or electrically via a motor operator that is automatically activated after the closing operation. The manual charging handle is retracted from the front panel and pumped to charge the springs fully. The handle freewheel after the spring is fully charged.

b. Incorporate mechanical operation counter

c. The breaker can be closed only after the mechanism is fully charged.

d. The closing coil shall have electrical anti pumping feature – The coil supply if maintained continuously will attempt to close the circuit breaker only one time. For the next closing operation the supply needs to be withdrawn and reapplied to close the circuit breaker.



e. Withdrawable version shall have intermediate position interlock.

f. Field installable internal and external accessories shall be possible

g. Auxiliary switches: Adequate number of auxiliary contacts shall be provided for the interlocking and indication function, plus 20% spare. Each contact shall have the AC and DC voltage rating of the intended application and a current rating of 6 Amps resistive and 10 Amps inductive.

h. Closing and open coils AC and DC voltage rating shall be adequate for the intended application.

7.4.2.6 Air Insulated Switchgear The switchgear shall comply with the requirements specified in IEC 60298 & 60694.

Table 2 Technical Data

Rated voltage: 6,6 kV

Rated frequency: 50Hz

Rated power freq withstand voltage (1 min): 20kV

Rated lightning impulse withstand voltage: 40kV

Rated short time withstand current: 3 sec 31.5 kA

Rated peak value withstand current: 100 kA

Rated duration time for short-circuit 3Sec

,

Height ≤2500mm

Depth ≤1000mm

Moreover:

a. T-off busbar rated current shall be ≤1250A.

b. Metering stacks, work shall be as defined during the design phase.

c. Units shall be suitable for top/bottom cable/busduct entry as required per layout design

d. Earthing switch shall be provided with interlocking arrangement



e. Marked with configurated single line diagram of the customized application

f. Provided with arrangement for surge suppressor mounting

g. Rear access terminations

h. Busbar plating – Silver or Tin.

7.4.2.7 Gear Compartments The Compartments shall be:

a. Designed with the sheet metal thickness 2mm.

b. Finish of the compartments shall be painted (Polyester paints) or Epoxy coated with the RAL color 7032.

c. Primary disconnects supported by polyester glass shall be provided.

d. Provision for control cable entry from the bottom front side of the bottom breaker compartment shall be provided.

e. Metallic shutters with option for padlocks shall be provided.

f. Gear compartment shall be fitted with anti condensation heaters.

g. Provision for keylocks and padlocks shall be there for different interlocks.

h. Circuit breaker compartment and cable compartment to have lifting type door to provide engagement on all four sides.

7.4.2.8 Circuit Breaker Compartment The compartment suitable for closed door racking. The withdraw-able mechanism through door shall offer racking operation of the breaker and allow different positions of the breaker “SERVICE” and ”TEST” (DRAWNOUT) positions.

The primary disconnecting multiple finger assemblies (clusters) shall be spring loaded and mounted on the circuit breaker with cluster pliers. They shall engage and disengage the primary conductors on the cassette back panel when the breaker is racked into the connected and disconnected positions.

The racking mechanism shall incorporates “SAFETY close prevention” feature.

The Circuit breaker shall not be possible to be inserted or withdrawn when breaker is closed.

Safety shutters shall be provided to shield the line and load stabs when the breaker is in withdrawn, disconnected or test positions inside the compartment. The shutters shall provide IP 30 level of protection to the live terminals. The shutters shall be pad lockable.



The racking mechanism and locks shall be located at the bottom of the cassette and accessible from front through the door cut out enabling the breaker to be disconnected from the mains supply without opening the door and access to live parts.

Compartment shall be provided with a rejection mechanism that shall consist of two parts, one mounted on the moving portion of the circuit breaker and the other part on the cassette which will enable only the properly rated circuit breaker to be inserted into the matched cassette. This shall be achieved with the control plug and socket pin configuration.

The Secondary disconnect blocks (control wiring plug and sockets) shall be located on the front top position for easy customer wiring.

Manual plug in/out shall have interlocks with the breaker service and test position.

The cassette shall be grounded on bottom side. Cassette grounding shall include an interface to the breaker earthing in service and disconnected position of the breaker in the cassette.

Both the associated relay compartment and circuit breaker front doors shall be hinged.

The circuit breaker front door shall have a window to view the position of the circuit breaker and the status of its closing spring. Doors should only be allowed to open with a tool and shall be padlockable in the closed position.

7.4.2.9 Cable Compartments The cable compartment shall be suitable for top cable entry (with additional cubicle) / bottom cable entry.

Provision shall be made for mounting lightning arresters, surge arresters or surge suppressers, Ground Fault (zero sequence) CT.

Provision shall be made for mounting up to three cables.

Provisions shall be made for CT mounting.

The cable compartment shall be suitable for cable glands.

Accessibility from rear / front side shall be provided.

7.4.2.10 Main Bus Compartment The main bus shall be supported at the sides of the stack using inter-unit bus supports. Standard inter-unit bus supports shall be of the polyester glass material, or equal, suitable for withstanding 80kA peak.

The main bus compartment shall have an air intake from the bottom rear cover and an air exhaust through the top cover.



Rear main bus barriers and front bus access barriers shall be of non-magnetic material (aluminium or stainless steel) for 2000A and above.

7.4.2.11 Insulating Supports Primary disconnects insulation, Inter-unit bus supports and bus support insulator shall be of the polyester glass / Epoxy material.

7.4.2.12 Ground Busbar Copper busbar with cross-section 8 x 30 mm, running through the length of switchgear shall be provided.

7.4.2.13 Buses and Connections Bus cross-sections shall be suitable for withstanding 100kA peak current.

Bus insulation shall be suitable for withstanding insulation levels of 20kV for 3 sec and 60kV peak impulse voltage.

Bus joints shall be covered with boots or taped.

Spacing for bus and other live parts shall be suitable for withstanding applied voltage to the specified insulation level.

Branch (feeder) connectors and insulation supports shall be suitable for withstanding applied currents corresponding to specified short time withstand capacity.

Copper bus shall be insulated with heat shrinkable sleeve manufactured by Raychem or equivalent.

7.4.2.14 Surge suppressor Surge suppressor shall be sized to operate within a 6.6kV rated system voltage and shall be fitted within a cable termination chamber.

7.4.2.15 Protection & Control Refer to Section 7.9

7.4.2.16 Earthing Switch Earthing switch shall comply with the ratings specified in IEC 60129.

The earthing switch shall be available for each feeder.

Provisions shall be made for manual operation from front.

Provisions shall be made for positive mechanical interlocked with the breaker and cable compartment door and interlocked with drawout location of the corresponding circuit breaker.



7.4.2.17 Black start Diesel Generator Medium Voltage Switchgear In addition to the requirements specified in this Section 7.4.2, the following specific requirements apply to the black start Diesel Generator MV Switchgear:

a. The switchgear panels shall be metalclad type with a three (3) stacked compartment design and shall comply with IEC 62271 standards.

b. The switchgear shall be designed for the safety of personnel against internal faults.

c. The switchgear panel shall be installed inside the electrical module (part of the diesel generator enclosure) with adequate clearances in front and back of the panel.

The switchgear and associated equipment shall be suitable for indoors use and shall be comprised of the following:

a. 6.6kV circuit breaker and busbars

b. 6.6kV fuse for the dry type auxiliary transformer

c. Surge and lightning protective equipment

d. Cable termination facilities for generator and load

e. Secondary wiring including cable termination facilities

f. Circuit breaker lifting provisions

The switchgear three (3) stack configuration shall include the generator circuit breaker at the bottom, 15kV fuses for the auxiliary step down transformer loads in the middle and the top shall have panels for bus PTs.

The generator vacuum circuit breaker shall be 3-pole, electrically operated with AC charge mechanism, 24V DC shunt trip coil, auxiliary switch contacts, and breaker drawout design with 25kA at 3 second short circuit rating.

7.4.3 LV common site switchgear, LV and DC switchgear LV switchgear shall be free standing and Form 4b in compliance with IEC 60439-1. For number of feeders, refer to the single line diagram. The LV switchgear will be controlled from the plant DCS. All LV and DC switchgear shall be GE or equivalent.

The short time rating shall be in accordance with the results of fault studies. Contactors shall be capable of withstanding the motor stalled current (rotor blocking current) until the associated protection device operates. Contactors shall comply with IEC 60439-4.



Composite fuse and switch equipment in the form of either a fuse-switch or switch fuse shall comply with IEC 60439-3.

Suitable handling equipment shall be provided for circuit breakers or starters that weigh more than 25 kg.

Mechanical or electrical safety interlocks shall be provided for isolation and maintenance and to avoid unsafe switching conditions.

7.4.3.1 Main Incomer Breaker Standards

All Low-Voltage circuit breakers shall use air as insulating means. Breakers shall comply with IEC Standard 947-1, 947-2 (BS EN 60947-2) and 947-3. All their electrical and operating characteristics shall be expressed in accordance with these standards.

General Operational Conditions

The reference ambient temperature shall be 55ºC.

The following are the general characteristics of the circuit breakers:

a. The operating mechanisms of the circuit breakers shall be of the “stored-energy quick-make” and “free-trip” type. They shall ensure “positive on” and “positive off” indications.

b. Their Thermal Rated Current rating shall be at least equivalent to the nominal current of the circuits they have to protect.

c. Their Rated Operating Voltage shall be at least equivalent to the rated voltage of the installation.

d. Their Rated Insulation Voltage shall be at least 750 V AC.

e. Their Service Breaking Capacity shall be at least equivalent to the maximum presumed three-phase short-circuit current which may occur on their out-going terminals.

f. Their Rated Making Capacity shall allow the breakers to be closed on the maximum presumed three-phase short-circuit which may occur on their out-going – terminals.

g. In order to ensure discrimination, all breakers of ratings above 630 Amp shall be of Category B. Their short-circuit current withstand capacity for 1 second shall be at least equal to the current corresponding to their Service Breaking Capacity.

7.4.3.2 Protection to be provided by the Air circuit breaker (ACB) The ACB shall provide protection against overloads, short-circuits, and, for specific breakers, Ground Fault Protection.



All ACB of rated currents above 160 Amp shall be equipped with solid-state trip units, not requiring any external auxiliary supply source for short-circuit and overload protection.

All settings shall be programmable on the field, without the use of any external device.

A means of connection shall be provided for an external test device, allowing for periodical tests of the status of the electronics of the trip unit.

To avoid un-authorized tampering, the trip unit shall be sealable once adjusted (key-lock, or seal), behind a transparent door or plate, allowing the settings to be visible.

For the protection against over-loads (“Long Time” protection LT and LTD):

a. The curve shall be of the inverse time/current type

b. To be adapted to the loads to be protected, the setting current of the LT protection shall be adjustable by steps between 0.4 and 1.0 times the rated current of the ACB.

c. The LT protection shall be adjustable by steps, allowing for curve- types adapted to line- or motor-protection.

A “pre-alarm” device shall be provided, to allow eventual load shedding before an over-load trip occurs.

A “thermal memory” shall be provided, adjustable to the type of load to be protected.

7.4.3.3 Protection against short circuits Delayed short-circuit protection shall be provided to allow discrimination with down-stream breakers, a delayed short-circuit protection shall be provided, with thresholds adjustable by steps, and ranging from 1.5 to 12 times Ir. The delay of this ST protection shall be adjustable from 0.1 to 1 second.

Instantaneous short-circuit protection shall be provided, over-riding the delayed short circuit protection, with its threshold adjusted to the current corresponding to the maximum breaking capacity of the ACB.

7.4.3.4 Ground Fault Protection ACB for specific Ground Fault Protection shall be equipped, next to the overload and short-circuit protections, with trip units ensuring Restricted-, Unrestricted- or Stand-by-earth fault protection (UEF, REF, SDF, to be defined on wiring diagrams).

UEF and SEF protections shall include an I2 t sensing device, allowing for an adjustable delay in the tripping time, to ensure discrimination with other down-stream ACB.

Over-ride protection and self-protection of the trip unit :--



Closing on a short-circuit, the breaker shall trip (“trip-free”) instantaneously. A specific “over-ride” protection, independent of the trip unit, shall ensure the trip when closing the ACB onto a short-circuit. This “over-ride” trip shall be inoperative if the short-circuit occurs with the breaker already in its closed position.

The solid-state trip unit shall be self-protected, and ensure the trip of the ACB in case of its malfunction. It shall enclose an “excess temperature” device and signal, which shall trip the breaker if the temperature inside its installation cubicle reaches a temperature, which may damage the ACB or the trip unit.

7.4.3.5 ACB MONITORING AND SIGNALLING The ACB shall be equipped with the following monitoring and signaling devices:

a. “Dry” Auxiliary and bell-alarm contacts on the ACB

b. Each ACB shall be equipped with a minimum of 5 free NO and 3 free NC auxiliary contacts, operating simultaneously with the ACB and rated for 10 Amp and 250V a.c.

c. Each ACB shall be equipped with at least 1 NO “bell-alarm” contact, which will be operated only when the breaker will trip on fault. This contact will only recover its open position after the reset operation of the ACB.

d. Each ACB shall be equipped with both a local indicator and an auxiliary contact indicating “springs charged” when its closing mechanism is ready for operation.

e. Alarm contacts on the Trip Unit: The trip unit shall have distinct local signalizations on its front part, showing its status: In-service; Over-load pre-alarm (current 1.1Ir, 60% of thermal memory consumed); Tripped on over-load; Tripped on delayed short circuit protection; Tripped on instantaneous protection; Trip unit malfunction.

f. The trip unit shall provide 3 out-put signals, indicating: Pre-trip alarm (current 1.1Ir, 60% of thermal memory consumed; Tripped on external fault (overload or short-circuit); “Load-shedding required” alarm

g. The trip unit shall also provide an out-put signal for “trip unit malfunction” .

h. A display shall show: the current flowing through the ACB (phase by phase); the number of mechanical operations of the ACB; The trip unit shall keep a record of up to the last 16 trips; The trip unit shall have at least 4 inputs for external tripping signals, allowing the ACB to be remotely tripped.

i. The communication features shall include: The trip unit shall be able to communicate bi-directionally, via an RS485 serial connection and MODBUS protocol; Out-put signals shall at least be able to communicate the signals above mentioned.

7.4.3.6 Operation of the ACB Closing of the ACB



All ACB shall be equipped with a “stored energy” closing mechanism.

Local operation: the springs required to store the closing energy shall be charged by means of a charging handle. The “close” operation will be carried out by means of the same charging handle, or by a green-painted push-button clearly marked “ON”.

Remote operation (for ACB with remote control only): an electrical motor shall charge the springs required to store the closing energy. The spring-charging shall not take more than 4 seconds. The ACB shall not initiate any “close” operation before its springs are fully charged. The remote “close” order will be transmitted by means of a closing magnet, requiring a pulse time of maximum 50 milliseconds.

In order to allow quick replacement and adaption to a different voltage, the closing coil shall be easily accessible from the front of the ACB, and require no tools for its replacement (“snap-on”).

Opening the ACB

Local operation: the ACB shall be opened by means of its operating handle, or by a red push-button clearly marked “OFF”.

Remote operation: The ACB shall be opened remotely by means of a shunt-trip coil, able to operate with voltages equal or above 70% of its rated voltage. The minimum pulse time in order to ensure its proper operation shall be of a minimum of 50 milliseconds.

The Shunt-trip coil shall be easily accessible from the front of the ACB, and require no tools for its replacement (“snap-on”).

7.4.3.7 Installation of the ACB The ACB shall be installed in appropriate cubicles inside the Switchboard, with the appropriate Busbars or cables, recommended by the manufacturer of the ACB for its nominal rated current. Dimensions and ventilation of the cubicle shall be sufficient to dissipate the heat generated by the ACB at its nominal rated current.

7.4.3.8 Clearance Distances The ACB shall comply with the following characteristics:

a. The ACB shall not require any clearance distances around its own physical dimensions, even if the cubicle walls are not covered with insulating materials.

b. Fixed ACB: Space shall be provided for the inspection and eventual replacement of the arc-chutes shall be provided above the ACB.

c. Terminal blocks of the auxiliary circuits terminals shall be easily accessible from the front of the ACB for wiring.



d. Withdrawable ACB: the ACB for mains incoming feeders, and for feeders out-going from the Busbars, shall be of the withdraw type.

e. The moving part of the ACB shall have 4 positions inside its fixed part.

f. To reduce the number of spare ACB, and allow minimum down-time, the fixed part shall have a memory device, storing all the parameters of its movable part, down-loading them automatically into the replacement ACB as soon as it is placed into the movable part and reaches the “test” position

7.4.3.9 Surge Protection Properly sized GE TVSS,or equivalent shall be used in each LV Switchgear/MCC to provide the required surge protection

7.4.3.10 Switchgear Tests The following standards and/or requirements shall apply to the switchgear tests:

a. Type tests made according to IEC 60439-1 (or equivalent standard such as BS EN 60439). The type test certificate shall be issued by an accredited laboratory and submitted for information to MoE.

b. Factory tests shall be done in according to IEC 60439.The relevant factory test certificate shall be submitted for approval. MoE shall have the right to witness each test. All living and travel expenses for MOE personnel shall be borne by the Contractor.

c. Clearance and creepage distances shall be in accordance with Tables 14 & 16 of Standard IEC 60439.

d. There shall be no unintentional disruptive discharge during the tests

e. Verification of short-circuit withstand strength (clause 8.2.3)

f. Test current for short-circuit withstand current for rising Busbars phase conductors shall be based on: Rated currents up to 1200A: 31.5kArms 3 second.

g. During the tests for short-circuit withstand strength, it shall be verified: that rising Busbar compartment doors and covers remained closed during the test; that full arc containment is achieved.

h. An accredited laboratory shall provide the certificate for the results of these tests

i. Verification of the effectiveness of the protective circuit (clause 8.2.4)

j. All parts of the switchgear combinations shall be effectively connected to the protective conductor, and this connection shall show a resistance below 0.5 Ohm.

k. After the test for the verification of short-circuit withstand strength of the protective circuit, the protective conductor shall not be impaired.



l. Verification of clearance and creepage distances (clause 8.2.5); It shall be verified that clearance and creepage distances are in accordance with Tables 14 & 16 of Standards BS EN 60439-1, considering a pollution degree 4; Minimum values for creepage and clearances combinations shall be used when dielectric properties are tested.

m. Withdrawable assemblies, if any, shall additionally endure dielectric tests in their “test” and “disconnected” positions.

n. Plug-in compartments, if any, shall additionally endure a dielectric test with the un-plug part taken out of the compartment.

o. Verification of Mechanical operation (clause 8.2.6).

p. A minimum of 50 mechanical operations shall be made on the mechanical functions of individual components and groups after installation into the assembly. At the same time, the operation of the functions of coupled & interlocking devices and mechanisms shall be checked.

q. Witdrawable compartments shall endure 50 mechanical withdraw/insert operations of the withdrawable part.

r. Plug-in compartments shall endure 50 mechanical plug-out/plug-in operations of their plug-in part.

The apparatus, interlocks, etc., shall operate properly and practically the same, after the testing operations, as before the test.

The degree of protection (clause 8.2.7), shall be verified according to IEC 60529, EMC tests (clause 8.2.8).

Only components that comply with EMC requirements shall be used within the assembly. If exceptionally required, the manufacturer shall provide a CE Declaration of Conformity, no further testing being required.

Routine tests For the fully assembled and installed motor control centre, the following routine tests shall be carried out by checking the assembly, wiring and electrical operations (clause 8.3.1)

a. Dielectric test (clause 8.3.2)

b. Checking of protective measures & electrical circuits (clause 8.3.3).

Verification of insulation resistance (clause 8.3.4): Before commissioning the motor control centre, the manufacturer, or the installer acting on his behalf, shall issue a compliance certificate stating all these routine tests having been made with positive results.

7.4.3.11 Tests According Other Standards Where required, for specific functions or components built into the motor control centre, specific compliance certificates may be required from the manufacturer.



In particular, compliance to the following Standards may be required:

a. BS EN 60204-1 Electrical equipment for industrial machines

b. BS EN 60364-4-41 Preventive Measures.

c. BS EN 60529 Ingress Protection

d. BS EN 60664-1 Isolation Co-ordination.

e. BS EN 60947-4-1 Motor Starters with Co-ordinated Short Circuit Protection, with voltage ranges & product ratings to VDE 0106 T100 (BGV A2) Type 2 coordinated.

7.4.3.12 Instructions for Installation, Operation and Maintenance The manufacturer shall specify in his documents or catalogues the conditions for the installation, operation and maintenance of the assembled motor control centre and the equipment therein.

These documents may also include the recommended extent and frequency of maintenance, and a list of recommended spares for the motor control centre and equipment therein.

7.4.4 LV and DC Switchgear

7.4.4.1 Structure The panel structure shall be made of steel. Partition steel plates, fastened to the structure, shall divide the motor control centre into compartments. The position of the partition steel plates shall be adjustable to easily adapt the height of the compartments in steps of 25mm.

Each compartment shall be closed by an individual practicable steel door on the front, and by independent steel covers on the sides and back. fully independent compartments shall be provided for:

a. Incoming section

b. Main Busbar

c. Cabling

d. Equipment

Extensions of the motor control centre, by addition of similar structures, shall be possible both to the right and to the left of the initial structure.

If the power centre feeding the motor control centre is provided, it shall be of the same structure and appearance as the motor control centre, allowing for an easy connection both to the right and to the left of the motor control centre.



7.4.4.2 Covers and doors All accessible parts of the motor control centre shall be conveniently earthed by their assembly means, and shall not require any supplementary specific earthing lead. When installed, covers and doors shall ensure a minimum IP30 degree of protection according to Standard BS EN 60529.

For plug-in or withdrawable equipment compartments, the door may be replaced by the front plate of the plug-in or withdrawable compartment.

Side- and back-covers shall be flush-mounted on the structure by means of spacers and self-tapping screws, which shall ensure the Earthing of the covers.

For ease of maintenance, the covers shall be interchangeable and re-usable on any compartment of the same height.

7.4.4.3 Doors The doors shall be provided with internal hinges, ensuring the Earthing of the door. The minimum opening angle of the door shall be 130 to 180 degrees. The doors shall be pre-punched to accommodate at any time door locks, meters, plates for auxiliary components, and louvers for ventilation.

Doors for switchgear compartments shall be provided with an interlock, avoiding the opening of the door without previously switching-off the voltage supply to the compartment.

Doors for Busbar, cable and meter compartments shall be equipped with a lock, to avoid unauthorised access to the compartments.

For plug-in or withdrawabe equipment compartments, the door may be replaced by the front plate of the plug-in or withdraw compartment. An interlock shall avoid un-plugging or withdrawing the compartment before its voltage having been previously switched off.

7.4.4.4 Compartments The different compartments formed by the partition plates, shall comply with the following conditions:

a. The incoming and the busbar compartments shall be separated from the other compartments by moulded plastic finger-proof shrouds.

b. The main Busbar compartment shall be located at the rear of the motor control centre, in a top or middle position.

c. The Busbar compartment shall contain all phase and Neutral conductors (if required), duly marked R,S,T

Protective conductors shall be located in a separate compartment, and shall be duly marked PE or PEN.

The Busbar shall be made of flat copper bars, of the same cross-section over the whole width of the motor control centre, and allow extensions of the motor control centre both left and right.

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All fixed connections shall be maintenance-free.

Separation links to adjacent columns shall be accessible from the front of the motor control centre.

The Busbar shall be supported by isolators, made of flameproof and leakage-proof material

For rated currents of 400A and above, flat copper bars shall be used, both for the Busbar and for the in-coming and out-going feeders.

The cable compartment shall contain the out-going terminals for main and control circuits. The cable compartment shall be located at the right of the motor control centre. The cable compartment shall be separated from the other compartments by metallic shutters providing a degree of protection of minimum IP20 according to Standard BS EN 60529.

Out-going feeders shall have a degree of protection of minimum IP20 according to Standard BS EN 60529, to avoid accidental contacts.

For out-going feeders of 630A and above, copper bars shall be provided as terminals, to allow the connection of several cables in parallel.

All connection terminals and cables shall be mounted in such a way as to avoid any traction or compression forces being exerted on them.

The bars- and cable- supports shall be designed to withstand the presumed short-circuit current.

Incoming and outgoing cables shall enter the compartment by the top and the bottom, with front and rear access provided to the connections.

The cable compartment shall contain a rising busbar, to feed the equipment compartments.

Equipment compartments shall be equipped with universal fixing plates, with holes in fixed steps allowing for the mounting of the different equipment and protection components. Each equipment compartment out-going feeder shall be protected by a 3 -pole air circuit breaker, or a 3-pole fuse-switch, or by fuses, of the corresponding rating and breaking capacity.

Meters and signal lamps shall be mounted on the hinged door of the compartment, which shall be pre-punched to accommodate standard instruments and signaling lamps and push buttons, or on the front plate of the compartment in plug-in or withdrawable compartments.

7.4.4.5 Form of Internal Separation Equipment compartments shall be separated from each other by finger-proof partitions.

Busbar and cable compartments shall be separated from the equipment compartments by finger-proof partitions.



The manufacturer shall indicate the Form of separation of the compartments according to informative Annex D of Standard BS EN 60439, Form 4b being the minimum required.

7.4.4.6 Protection and finish All steel parts forming the structure shall be protected by a zinc coating, providing protection against corrosion according to Standard EN 10142.

All ferrous parts e.g. hinges, mounting parts, shall be protected by an electro-galvanic zinc coating.

Protection shall be verified in accordance with Standard BS EN 50298.

Following tests shall be made:

a. “Wet heat”, 6 cycle 24hours with 95% relative humidity at 40ºC, according to Standard IEC 68-2-30

b. “Salt fork”, 2 cycle 24hours at 35ºC, according to Standard IEC 68-2-11

Covers, doors and front plates shall be made of 2mm steel sheet to ensure stability. All edges shall be bent-over to avoid sharp edges. All external doors, covers and front-plates shall be flush-mounted to the structure. No hinges, fixing screws or bolts shall be visible from the front of the motor control centre. All external parts shall show a uniform colour, preferably RAL 7032 (light grey) applied through an epoxy powder painting of minimum 75 µmm thickness.

7.4.4.7 Electrical Characteristics The motor control centres shall be designed according to the following electrical characteristics:

a. Rated operational voltage: 400 v ac

b. Rated insulation voltage: 1000V

c. Impulse withstand voltage: 8kV 1.2/50µs

d. Rated frequency: 50 Hz

Minimum Rated short time withstands current for rising busbar phase conductors with:

a. Rated currents up to 850A: 40kA, 1 second

b. Rated current 1200A: 50kA, 1 second

c. Rated currents 1550A: 65kA, 1 second

d. Rated currents 1550A: 80kA, 1 second

Minimum Cross-sections for Neutral conductor (if required) and PE or PEN conductor:



Rising Busbars with phase conductors with rated currents:

a. Up to 850A: 375mm2

b. 1600A: 525mm2

c. 1550A: 675mm2

d. 1900A: 825mm2

7.4.5 Emergency diesel Generator LV/MCC Panel In addition to the requirements in this Section 7.4.4, the following are the specific requirements that apply to the Diesel Generator LV Switchgear/MCC:

a. The insulation rating of the panel & bus bar shall be based on 1000 VAC, and shall comply with all applicable IEC standards.

b. Each distribution board or panel shall be furnished with an engraved plastic or metal name plate on the front with all necessary information (name of consumer, location, main fuse rating and feeder cable size).

c. Inside each distribution board a directory sheet in transparent plastic cover shall be fitted, with necessary information for all feeders (load reference, location, fuse rating). Protection shall be provided against accidental contact. All steel enclosures including doors shall be earthed. The distribution panel shall be constructed and designed per applicable IEC requirements.

d. Cable terminations and identification shall be made in accordance with IEC/EN 60947.

e. A sufficient number of spare circuit breakers (20%) shall be included within the design for future use.

f. All circuits shall be protected by automatic circuit breakers.

g. The LV /MCC shall provide diesel generator auxiliary controls such as radiator fans, ventilation fans, air compressor, fluid heater and the single phase supply for the enclosure genset.

7.5 Current transformers All current transformers shall comply with IEC 60044-1. CT secondary windings shall be earthed at one point only through an accessible link. The secondary windings rating shall be subject to MoE approval.Facilities shall be provided to allow primary injection testing with minimum disturbance to the equipment. The following accuracies shall be used:

a. Tariff metering Class 0.2

b. Instruments Class 0.2



c. Differential protection Class 5Px

d. Other protection Class 5Px

The contractor should make calculation for CT Burden according to relevant IEC standard and submitted for the approval of MOE .

7.6 Voltage transformers All voltage transformers shall comply with IEC 60044-2. For MV applications the primary windings shall be connected through renewable fuses. The secondary winding of all VTs shall be provided with an accessible phase coded fuse or miniature circuit breaker. VT secondary circuits shall be complete and earthed at one point only. It shall not be possible to connect VT secondary circuits in parallel where the VTs are connected to different sections of busbar. The following accuracies shall be used:

a. Tariff metering Class 0.2

b. Instruments Class 1.0

c. Protection Class 3P

The contractor should make calculation for PT Burden according to relevant IEC standard and submitted for the approval of MOE.

7.7 DC supplies system The charger shall be provided with voltmeter, ampere meter, on/off switch and trip indication. The charger shall include sufficient dry contacts for remote monitoring/alarm indication

Contractor shall furnish 2 (two) 110 dc battery system 2 (two) three phase chargers (one for each battery system). Contractor shall also furnish 2 (two) sets of 48 dc systems, with the same structure of 110Vdc system. Battery sizing shall be done as per Relevant Standard . The rating of the batteries shall include adequate design margins and aging factors that will be finalized during the design phase of the project.

Each battery shall be rechargeable alcaline type and it shall be complete with stands, all intercell connections, and connections between the battery terminals, chargers and the switchgear.

Indicating lamps shall be provided on the equipment to indicate battery faults, the faults shall also be remotely indicated to the plant control system.

Batteries shall be sized to feed all basic station instruments for at least 5 (five) hours.

Battery chargers shall have natural cooling. It shall be possible to carry out maintenance on one charger with the other in service. Each charger shall be capable of recharging the battery within 5 (five) hours after a complete discharge.



The battery rooms and the battery acid store shall be adequately ventilated to ensure that the level of hydrogen gas present is less than 1 per cent; their lighting and socket system shall be as per IEC 60079.

The DG (Diesel Generator) shall include 24 volt DC sealed lead acid batteries sufficiently sized to maintain voltage and amperage requirements of all DC components, including but not limited to switchgear, DG control panel and emergency lighting without charge for eight (8) hours. The batteries shall be installed in a work safe location inside the electrical module. Battery terminals shall include a non-conductive protective cover. The batteries shall be recharged using alternatively a static battery charger (typically a rectifier bridge) and a belt driven rotating battery charger moved by the engine itself.

The static battery charger shall be single-phase voltage per site data specification sized to provide 150% of total DC circuit load. The power shall be routed from the LV panel and connected to the essential LV bus.

7.8 Uninterruptible power supply equipment The UPS equipment shall have isolation facilities to permit full replacement without disrupting any part of the system to which it is normally connected.

The equipment shall be complete with local alarms and a common alarm shall be repeated to the plant control system.

The UPS shall comply with IEC 60146-4.

Neutral earthing mode for UPS shall comply with other systems.

7.9 Protection

7.9.1 General High speed discriminative protection systems shall be engineered as complete schemes, with due account being taken of current and voltage transformer performance. All protection relays shall be Multilin or equivalent.

All relays performing a measuring function shall be of numerical design with continuous self-monitoring.

Numerical relays and schemes provided shall all be suitable for connection to a local communications network, and provided with an integral local user interface.

The communication network details will be finalized during the design phase of the project.

Protection relays shall be type tested in accordance with the relevant sections of IEC 60255. Each protection relay shall have means by which the user can apply the settings, and a unique identifier which is clearly visible.



All back up protection systems shall be able to discriminate with main protection systems, circuit breaker fail protection (if fitted) and other back up protection systems installed elsewhere on the system.

Adequate facilities shall be provided within the protection scheme to enable the protection equipment to be tested from the front of the protection equipment panel with the primary circuit(s) in service with test points clearly labeled.

The protection system shall operate satisfactorily when tested to IEC 60068-2, IEC 60255-21, and IEC 60255-22.

The relay shall be provided in one integrated package suitable for incorporation in an integrated substation control system. It shall be a modular design to easily facilitate upgrading or repair by replacement of modules. Modules shall not have exposed circuitry and shall be self encapsulated for maximum protection. Modules connecting to current transformers must automatically short circuit the CT upon withdrawal of the related protection relay(s).

The use of remote inputs and outputs in addition to hardware shall be available on the communications ports using IEC-61850 GOOSE as a mechanism to minimize the requirement for auxiliary components and wiring. The contact inputs shall accept wet or dry contacts. Contact outputs shall be trip rated Form-A with current and voltage circuit monitors, Form-C, or Fast Form-C for signaling. Hardware input/output capability shall be expandable.

The relay shall have three communications ports that operate independently and simultaneously. The RS232 port shall be accessible from the faceplate of the relay. The second port shall be RS485 supporting ModBus® RTU and DNP 3.0 protocols capable of baud rates up to 115 kbps. The third communications port shall be either a similar RS485 port or a 10/100 Mbps Ethernet port supporting IEC-61850, ModBus®/TCP, and DNP 3.0 or IEC 60870 protocols. The physical port shall be 10/100BaseF, or redundant 10/100BaseF.

The relay shall be supplied with supporting application software for use on a PC with Windows® XP/Vista/Linux operating systems. The program shall be capable of retrieving Comtrade oscillography files from the relay to display, save, or print when troubleshooting. The software shall provide the capability of editing and managing settings files to store to the relay or disk backup, while on-line or off-line. The software shall also permit the updating of new relay firmware and viewing of all trip and alarm target messages, and the 1024 time stamped events recorded by the relay.

The software shall be capable of changing the modules internal configuration as needed in different protection schemes.

The relay clock shall be capable of being synchronized with an IRIG-B signal to allow synchronism with other connected devices. The relay shall allow for SNTP network-based time synchronization.



7.9.2 Transformer protection Protection of small Auxiliary transformers shall be provided by feeder protection relays as described in section 7.9.4 below and over temperature (oil and winding) and low oil level protection. The Generator Step up and Unit Auxiliary (UAT), Transformer protection and control shall be provided in one integrated package suitable for incorporation in an integrated substation control system. The relay shall be applicable to transformers with up to five windings/restraints (UR-T60, SR345 or MoE approved equivalent). The relay shall be based on a common modular platform.

: As a minimum, it shall have the following protection, control, metering and monitoring functions and communications

a. Transformer differential (87T)

b. Maximum number of windings

c. Harmonic restraint

d. Internal winding phase shift compensation

e. Dynamic CT ratio-matching

f. CT mismatch range of 32/1

g. Restricted earth fault (87REF)

h. Volts per Hertz (overfluxing) (24)

i. Phase undervoltage (27)

j. Instantaneous overcurrent for phase, neutral and earth protection (50/50N/50G)

k. Inverse timed overcurrent for phase, neutral and earth protection (51/51N/51G)

l. Custom programmable overcurrent curves

m. Overvoltage (59)

n. Neutral overvoltage (59N)

o. Overvoltage – Symmetrical components

p. Directional control for phase, neutral and earth (67/67N/67G)

q. Voltage transformer fuse failure

r. Under/over frequency protection (81U/81O)



s. Synchrocheck (25)

t. Transformer overload (49)

u. Up to 6 setting groups

v. User programmable LEDs up to 48

w. Analog inputs

x. Analog outputs

y. RTD inputs up to 24

z. Metering: I(RMS), I(Phasor), I(demand), I(Unbalance), I (harmonics up to 25th),V, Watt, Var, VA, pf, Watt (demand), Var (demand), VA (demand), Wh, Hz, Temperature, KA2, loss of life

aa. Event recorder – Up to 1024 events time stamped to 1 msec accuracy

bb. Trip counters, data logger

As minimum, oil filled transformers shall be provided with the following supplementary protection devices:

a. Buchholz – main tank and OLTC

b. Over temperature – Oil and winding

c. Over pressure

d. Oil level

e. Sudden pressure rise

f. Power supply supervision

7.9.2.1 Biased Differential Automatic ratio and vector group compensations shall be included.

The protection shall be based on dual breakpoint, dual slope differential/restraint characteristic using maximum winding current for restraint.

The element shall include built-in magnetizing inrush and overexcitation inhibits. The inrush inhibit feature shall provide choice for per-phase, cross-phase or average blocking.

7.9.2.2 Instantaneous Differential The protection shall respond as instantaneous overcurrent element on differential currents



7.9.2.3 Overcurrent Protection Multiple phase inverse time overcurrent elements shall be provided.

Inverse time overcurrent curve characteristics: IEEE, IEC, IAC, I2t, definite time, and four custom curves for precise or difficult coordination shall be available.

7.9.2.4 Control Functions Programmable logic including non-volatile latches

Suitable for user-definable protection functions

Flexible control of all input and output contacts shall be provided.

All elements shall have a blocking input that allows supervision of the element from other elements, contact inputs, etc.

The relay shall allow for peer-to-peer communications direct fiber or G.703 or RS422 interfaces.

The relay shall have switchable setting groups for dynamic reconfiguration of the protection elements due to changed conditions such as system configuration changes, or seasonal requirements.

7.9.2.5 Metering and Monitoring Functions Differential and Restraint Currents: Per-phase differential and restraint currents – magnitudes and angles, as well as per-phase differential 2nd and 5th harmonic levels (percent and angle).

Voltage, Current, Power Metering: Voltage (phasors, true RMS values, symmetrical components), current (phasors, symmetrical components, true RMS values), real, reactive and apparent power, power factor and frequency.

RTD transducer inputs

User-programmable oscillography – up to 64 samples per cycle

Trip circuit monitoring

7.9.3 Medium and high voltage motor protection relay Protection, monitoring and metering shall be supplied in one integrated digital relay package for application to medium and large horsepower motors suitable for incorporation into an integrated station control system. The relay shall be based on a common modular platform.

The relay shall be provided in one integrated package suitable for incorporation in an integrated substation control system. It shall be a modular design to easily facilitate upgrading or repair by replacement of modules. The faceplate interface shall include LCD display, keypad, and LED target indicators.



7.9.3.1 Thermal Overload Protection The Thermal Overload element must provide dynamic rotor protection both during acceleration and stall conditions. The algorithm shall include these key elements:

a. Overload protection using Standard and user-programmable overload curves.

b. Negative sequence current biasing using the negative to positive sequence ratio scaling to include system unbalance heating effects.

c. Stator RTD biasing (hot/cold compensation) with type selection.

d. Independent motor cooling time constants for both running and stopped conditions.

e. Restart inhibition to prevent thermal damage during successive starting.

f. Inhibit override to allow an Emergency restart.

7.9.3.2 Restrained Stator Differential element The differential element shall have a dual slope characteristic.

A directional check and saturation detection algorithm shall be included for enhanced performance during CT saturation.

7.9.3.3 Current Unbalance protection This element shall use the negative to positive current component ratio method.

The element shall adapt to overload conditions.

The element shall detect “single-phasing” .

7.9.3.4 Overcurrent Protection Phase, Neutral, and Ground Instantaneous Overcurrent (IOC) protection shall be provided with a settable time delay.

Ground Time Overcurrent (TOC) protection, with: IEEE, IEC, IAC, I2t, definite time curves.

7.9.3.5 Voltage Protection Phase, Neutral, Auxiliary and Negative Sequence overvoltage protection

Phase and Auxiliary undervoltage protection, both with definite and inverse time characteristics

The voltage element operating times shall be user adjustable.

7.9.3.6 Sensitive Directional Power element Two elements shall be included each consisting of two stages.



The element characteristic angle shall be adjustable.

7.9.3.7 RTD monitoring

7.9.3.8 Programmable logic including non-volatile latches

7.9.3.9 User-definable protection functions All elements shall have a blocking input that allows supervision of the element from other elements, contact inputs, etc.


7.9.3.10 Switchable Setting Groups The relay shall have switchable setting groups for dynamic reconfiguration of the protection elements due to changed conditions such as system configuration changes, or seasonal requirements.

7.9.3.11 Voltage, Current, Power, Energy Voltage (phasors, true RMS values, symmetrical components), current (phasors, symmetrical components, true RMS values), real, reactive and apparent power, power factor, energy and frequency.

7.9.3.12 User-programmable oscillography (up to 64 samples per cycle)

7.9.3.13 Trip circuit monitoring

7.9.4 Feeder Protection Bay Controller units must be digital, 32-bit RISC microprocessor-based devices providing protection, control, monitoring, metering, and register functionality for a substation bay. Separate tasks firmware scheduling for protection and other tasks ensures the best dependability and security. A redundant power supply shall be optionally available for each unit. Unit architecture shall be modular allowing flexible analog and digital I/O by the addition of single card modules. Extended I/O capability will be available through distributed I/O modules using fiber optic CAN bus.

7.9.4.1 Protection Available units for different bay applications (feeder, capacitor banks, auxiliary services control...) including all typical protection functions: 50, 51, 67, 46, 27, 59, 59N, 81U, 81O, 25, 79, 50BF

Cold load pickup

Selectable setting tables

Configurable inputs and outputs through the use of advanced IEC-1131 PLC block diagram standard programming

7.9.4.2 Metering Ia, Ib, Ic, In, Ig, I2, Vab, Vbc, Vca, Vbb, P, Q, f, pf and energy real-time metering



Current maximum demand metering

Data logger

Class 0.5% metering for both current and voltages. 1% for power and energy

Pulse counting for energy metering also available

7.9.4.3 Monitoring Real time monitoring of up to 32 switchgear elements (breakers, switches,...)

Alarm generation and treatment

Breaker supervision (I2t)

Breaker coil supervision

7.9.4.4 Register and Analysis Functions Event register

Oscillographic register with programmable sampling rate and depth.

7.9.4.5 Control Functions Programmable operations for up to 32 elements (programmable operate, fail and success conditions and operation timers)

Programmable interlockings

Configurable inputs and outputs

Configurable one line diagram for the substation bay

7.9.4.6 HMI and Communications Local alphanumeric 4 lines x 20 characters LCD for protection operation

Front RS232 communications port

Rear redundant RS485 or plastic fiber optic or glass fiber optic async port

Rear Ethernet 10/100 Base T sync port

Optional 100 Base F fiber optic, single or redundant for sync port

7.9.5 Low impedance busbar protection system Low-impedance bus differential protection with enhanced immunity to CT saturation shall be provided in one integrated package suitable for incorporation in an integrated substation control system. The relay shall



be applicable for single-busbars, double-busbars, triple-busbars with or without a transfer bus, meshed corners and breaker-and-a-half arrangements of a total of up to 24 current inputs. The relay shall be based on a common modular platform such as the UR-B30 or B90 designed to serve as the engine for industrial & utility substation automation.

The busbar protection system shall have the following architecture:

Phase-segregated low-impedance solution shall be provided.

The scheme shall be configured using several separate UR IEDs.

Inter-IED communications shall be provided by means of dual-ring direct fiber connection.

Each IED shall accept a common setting file format.

Each IED shall be accessed simultaneously from the same PC configuration program.

The scheme shall allow for flexible distribution of digital inputs and output contacts between the IEDs.

7.9.5.1 Restrained Bus Differential The element shall use two voltage-independent protection principles, current differential and phase comparison, with additional CT saturation detection.

The differential principle shall be based on dual-slope dual-breakpoint characteristic with the maximum zone current used for restraint.

The phase comparison principle shall check directional relation between the relevant zone currents to differentiate between internal and external faults. Selection of the currents for comparison shall be adaptive.

The CT saturation detection mechanism shall distinguish between internal and external faults having as little as one-eighth of a power system cycle of undistorted current waveforms.

Automatic CT ratio compensation shall be included.

7.9.5.2 Unrestrained Bus Differential

7.9.5.3 Overcurrent Protection One time overcurrent element shall be provided per each current input of the relay.

Time overcurrent curve characteristics: IEEE, IEC, IAC, I2t, definite time, and four custom curves for precise or difficult coordination shall be available.

One instantaneous overcurrent element shall be available per each current input of the relay.

7.9.5.4 Voltage Protection One undervoltage element shall be provided per each voltage input of the relay.



7.9.5.5 Breaker Failure One breaker fail element shall be available per each current input of the relay.

The breaker failure protection shall respond to three levels of current in three-pole and single-pole modes as well as to breaker contacts.

7.9.5.6 End Fault Protection One end fault protection element shall be available per each current input of the relay.

7.9.5.7 CT Trouble The element shall respond to differential current and when used in conjunction with voltage supervision or a check-zone shall provide desired response to CT fail conditions.

7.9.5.8 Dynamic bus replica The relay shall allow associating a dynamic connection status signal with each input to the differential element in order to dynamically include or exclude a given current from the differential calculations.

The status signal could be any user flag available in the relay, especially position of any input contact or a combination of thereof via programmable logic.

The relay shall allow inverting any given current in software before configuring it for the bus differential zone. This allows easier application to bus couplers with single CTs.

7.9.5.9 Isolator Monitoring The relay shall provide for isolator monitoring functions responding to both normally open and normally closed auxiliary switches.

Isolator contact discrepancy alarm shall be incorporated. A provision of blocking switching operations in the substation, blocking selected protection functions and acknowledging the alarm shall be made.

The functional shall generate a reliable isolator position signal even during contact discrepancy situation.

7.9.5.10 Programmable logic including non-volatile latches

7.9.5.11 Inputs/Outputs Flexible control of all input and output contacts shall be provided.

All elements shall have a blocking input that allows supervision of the element from other elements, contact inputs, etc.


7.9.5.12 Switchable Setting Groups The relay shall have switchable setting groups for dynamic reconfiguration of the protection elements due to changed conditions such as system configuration changes, or seasonal requirements.



7.9.5.13 Currents and Voltages metering Voltage (phasors, symmetrical components), current (phasors, symmetrical components, true RMS values), and frequency.

Differential and restraint currents shall be available in terms of magnitude and angle for easy testing, commissioning and troubleshooting.

7.9.6 Black start diesel generator and emergency diesel generator protection The generating unit shall be provided with protection equipment which shall protect the generating plant from damage due to fault conditions. All relays or similar equipment for overspeed, oil pressure, cooling water level and high cooling water temperature, directly associated with the prime mover shall be mounted on the generating set engine and associated with a suitable trip relay. Protection equipment shall be provided and arranged to trip the associated circuit breaker, suppress the excitation and shut down the prime mover if faults should occur. Synchronizing, auto-manual operation, local and remote indications, etc shall be provided. The generator shall be provided with the following protection functions as a minimum:

The primary protection for the AC generator shall be provided in one integrated package suitable for incorporation in an integrated substation control system.

As a minimum, it shall have the following protection, control, metering and monitoring functions and communications:

a. 100% Stator Ground

b. Accidental Energization

c. Loss of Excitation

d. Sensitive Directional Power

e. Overexcitation

f. Under and Over Frequency

g. Overcurrent and short circuit Protection

h. Differential protection

i. Under and Over Voltage Protection

j. Programmable logic including non-volatile latches

k. Monitoring Functions

l. User-programmable Data Logger



m. Winding and bearing temperature supervision

n. Earth Fault Protection

7.10 Diesel Generator Set Synchronizing Each diesel generating set shall be provided with an auto-synchronizing scheme, synchronizing the generator across its circuit breaker.

7.11 The scheme shall be provided with a check synchronizing relay and selector switch for manual, auto, test and off. The test position shall be a simulation of the circuit breaker closing. Black start diesel generator

The black start/emergency diesel generator shall be 1000 RPM or less with electronic fuel direct injection, compression ignition, turbocharged and charge air cooled industrial engine of standard design and construction. The black start diesel generator shall be sized at least 4MVA with 0.85 power factor. The final rating of the black start diesel generator shall be based on load profiles for the auxiliary electrical systems, which shall be finalized by the contractor during the design phase of the project.

Parallel operation shall be allowed only to allow a bumpless commutation between black start diesel generator and mains. Immediately after a successful commutation, black start diesel generator circuit breaker shall open. The sudden removal of 100% load shall not cause shutdown for overspeed.

The diesel generator set shall be enclosed type designed suitable for desert environment. The enclosed unit shall be a complete, self-contained, enclosed unit that includes the diesel engine and generator mounted on a common base frame, a standalone electrical enclosure housing the switchgear and associated control systems, and a mechanical enclosure house the engine auxiliaries along with a standalone radiator assembly. The system shall be capable of delivering continuous electrical power at varying load. The generating set shall be equipped with interlocking relays in order to avoid misoperations.

The generator shall be of the brushless type with Class 155(F) insulation with temperature rise and total temperatures limited to Class 130(B) limits. The generator shall be in accordance to IEC 60034 and ISO 8528 standards. The generator nominal voltage shall be 6.6kV.

The generator sets shall be rated for continuous duty with varying load and operated with load factors up to 100% of the continuous power rating for an unlimited number of hours per year without derating.

The engine shall be Medium speed equipped to operate on diesel fuel and include a cooling system, with engine driven water pump.

The Black start diesel generator shall be sized to allow feed all operating duty loads and all unit loads needed to start up one unit at the same time.

The engine rating shall be in accordance with ISO 3046 under the required site conditions.



The engine flywheel shall be suitable for the required starting duty.

Turbochargers shall be exhaust gas driven.

Engine governors shall be in accordance with ISO 8528, performance class G2 as minimum. The electronic control, with speed adjustment devices, shall be mounted and wired in the diesel generator control panel.

The unit shall be complete with a local control panel which shall be interfaced to the plant control system.

The genset cooling system shall be a two–loop system: the engine cooling loop and the auxiliary cooling loop to cool the water flowing into the intercoolers.

The engine radiator(s) shall be remote mounted in a horizontal configuration, with vertical discharge and shall include an expansion tank and temperature controlled modulating valves to bypass the radiators when cooling is not required

The engine lubrication system shall consist of a gear-driven pump to circulate lube oil through the engine and a water-cooled plate or tube style oil cooler to remove the heat from the system.

The engine shall be equipped with immersion type jacket water and lube oil heaters, thermostatically controlled, to maintain engine block coolant temperature ready to accept loads upon loss of normal power. The heaters shall be specifically designed to keep the engine in a state of constant readiness for operation

The diesel generator integral double walled fuel tank shall have a capacity of [eight] hours. All piping, valves, pumps/motors and their controls shall be provided to facilitate filling the diesel generator fuel tanks from the Plant diesel fuel storage tanks. The lubricating oil system shall be self contained independent pressurized serving all the engine requirements.

7.11.1 Starting System The engine starting system shall be by air-operated motor connected to the engine flywheel. An electric driven compressor shall be provided to recharge the air receivers. The compressed air shall be stored in a receiver tank capable of a minimum of five (5) starts without the compressor being recharged

It shall be possible to test the diesel generator periodically. During periodic testing all engine protection, alarms and trips shall be operational. During periodic testing the load on the essential supplies/common switchboard shall be synchronized and transferred to the diesel generator.

The generator shall be of the brushless type with Class F insulation and temperature rise. The generator shall be built and tested in accordance to IEC 60034 standards.

Under black start conditions, and where there is more than one gas turbine, a gas turbine shall be selected for start. A coded key/electrical interlock shall ensure that only one gas turbine can be started at any one time. The coded key/electrical interlock system shall encompass the MV circuit breaker which supplies the site Auxiliary transformer used as emergency transformer, ensuring that it will not be possible to start a gas



turbine whilst the diesel is supplying the essential supplies/common switchboard and vice versa. The circuit breaker on the secondary side of the emergency transformer shall be interlocked to ensure that the emergency transformer cannot be paralleled with any other incoming supply to the essential supplies/common switchboard.

7.11.2 Generator Local Control Panel The engine generator control panel shall be installed in the electrical enclosure. The Generator Control system shall include a microprocessor based Diesel Generator management system with functions for metering, protection, power / control and monitoring with all monitoring read-outs displayed on the operator interface module with color touch screen. The Diesel Generator control system shall be capable to perform based load and island operation and automatic and manual synchronizing to the plant power system.

The diesel generator control system shall include provision to allow external communication to a central control room to allow power monitoring. Communication shall be via Ethernet Modbus Protocol.

The local control panel shall provide for complete control and monitoring of the engine and generator set functions via the operator interface terminal. These shall include but not be limited to automatic start/stop operation; adjustable cycle cranking, digital engine monitoring, shutdown and alarms with reset and emergency stop push-button.

The operator interface terminal display shall include but not be limited to the following graphical readouts:

a. Engine oil pressure

b. Engine Coolant temperature

c. Engine Speed

d. System DC Volts

e. Generator AC volts

f. Generator AC amps

g. Generator frequency

h. kW meter

i. kVA meter

j. kVAR meter

k. Power Factor meter

l. kWHR meter



7.12 Emergency Diesel Generator The emergency diesel generator shall have the same features stated for Black Start Diesel Generator.

The emergency diesel generator shall be sized at least 1.25 MVA at 0.85 power factor. The emergency diesel generator shall allow the emergency shutdown of all the turbines of the plant and feed all the emergency loads at the same time.Parallel operation shall be allowed only to allow a bumpless commutation between emergency diesel generator and mains. Immediately after.a successful commutation, emergency diesel generator circuit breaker shall open. The sudden removal of 100% load shall not cause shutdown for overspeed.

7.13 Tariff Metering The tariff metering system shall include main and check meters. All meters shall be suitable for three phase imbalanced loads, be Class 0.2, and shall comply with IEC 60687. The output from the meters shall be accessible from the plant control system. The metering system shall measure each generator output, and the import and export of the total power station active and reactive power.

7.14 Motors for Pumps and Electrically Operated Valves Motors shall comply with the requirements of IEC 60034 and IEC 60072. All motors rated 100kW and above shall be fitted with winding and bearing temperature detectors and vibration monitoring. Motors rated 200kW and above shall be medium voltage.

Motor enclosures shall be IP54 for indoor applications and IP55 for outdoor applications, and shall be totally enclosed fan cooled.

Winding insulation shall be to Class 155 (F) with temperature rises and total temperatures restricted to Class 130 (B) limits.

All MV motors and all outdoor LV motors shall be fitted with anti-condensation heaters.

Rolling element type bearings shall comply with ISO standards. Oil lubricated bearings shall be fitted with an accessible drain plug, and means of observing the oil flow.

For Contractor furnished motors, terminal boxes shall be totally enclosed to prevent the ingress of dust and moisture. The supply cable shall have a separate terminal box. LV motors shall have insulating barriers between terminals; MV motors shall have phase segregated terminals. Materials for air coolers shall be selected to provide resistance to corrosion.

7.15 Earthing The Contractor shall conduct a site survey/geotechnical investigation to determine the soil electrical resistivity as per IEEE 81, Section 7 utilising the four point method. Results shall be graphed – Resistivity (ohm-meters) vs. Probe Spacing. Probe spacing shall be 0, 3, 5, 10, 20 & 30 meters. Readings shall be taken at each corner of the project site, and on a 60 meter grid spacing within the perimeter of the project site. The resistivity survey shall be performed after exploration borings have been performed, and the geophysicist

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performing the resistivity survey should be informed of the results of the subsurface explorations. Thermal resistivity survey shall also be made. Based on these results the Contractor shall determine the touch and step potentials of the new system, or extension to an existing system where applicable. The design and installation shall comply with IEEE 80, IEEE 665, IEEE 1050, BS 6739 and BS 7430. The maximum resistance of the grid shall one ohm (0.5 Ω) or less. The earthing system shall take form of a combination of copper earth rods driven into ground vertically at corners of grids of buried copper conductors. Grids shall be of fairly equal size to the extent practicable. Earth network shall be suitable to withstand fault currents upto 0.5 sec but the minimum size of conductor shall not be less than 120mm2 in any part. Any non current carrying metal structure that may accidentally become part of current carrying path to ground, such as equipment safety ground, shall not be less than 70 mm2.

Connections to existing systems and substation earthing systems shall be made by disconnecting links readily accessible for test purposes.

All disconnecting links and distribution bars shall be supported from insulators.

Earthing distribution bars shall be strategically positioned around the plant areas.

All metallic casings, frames and tanks of electrical equipment shall be bonded to the earthing system, along with all structural steelwork, metallic fences and gates, tanks and steel reinforcing.

Connections to electrical equipment, at two points, shall be detachable from the earthing bolt or stud. Cable trays and ladder racking shall be earthed at regular intervals.

Switchboard earth bars shall be connected to the earthing system at each end of the equipment.

Dedicated earth bars and disconnecting links for electronic equipment shall be clearly identified.

The earthing system within buildings shall comply with BS 7671.

Pipelines entering the site shall be fitted with an insulated flange at the boundary. The minimum resistance across the flange shall be one thousand ohms (1 kΩ).

Conductors shall be stranded high conductivity copper to IEC 60228. Solid rods or bars shall be to BS EN 13601.

Where ground rods are used they shall be hard drawn high conductivity copper with hardened steel driving caps and tips.

7.16 Cabling

7.16.1 General The cable installation shall be complete with all terminations, trays, ladder racks, glands, ferrules, lugs, markers, and fixings.



Cables shall be in one continuous length, have high conductivity copper conductors, and comply with IEC 60332-3.

Medium and low voltage power cables shall comply with IEC 60502 and IEC 60811. The Contractor shall prepare voltage drops and sizing calculations.

The conductor cross section of each cable shall be adequate for carrying the prospective fault current determined by the next upstream short circuit protection device.

The contractor shall conduct voltage drop calculations, based on the distance and routing of the cables, to determine the adequate number of conductors and sizing for each application. The voltage drop between the point of supply and the fixed equipment shall be limited to x 5per cent.

All power cables shall have phase identification. The phase identification terminology shall be defined during the design phase of the project.

Galvanized steel wire armour shall be used for multicore cables, aluminium wire armour for single core cables. Where cables are routed on cable trays or in metal conduits, not exposed to open air, not laid direct in ground, i.e. if contractor can demonstrate that any possibility of damage to cables is non existent; in such cases unarmoured cables may be used subject to MoE’s approval.

Single core power cables shall be earthed at one end only.

Building services wiring shall have extruded XLPE insulation.

The following separation guidelines shall be used to reduce the possibility of electrical interference between various voltages and power levels.

Each electrical circuit will carry an electromagnetic “level” designation. Cables of like levels may be run together in conduits or trays and unlike levels shall be run in separate conduits or trays as defined in the unlike classes. Intermixing of circuit levels is not allowed in the same raceway except for specific applications. Four basic levels are used:

Level 1—Low Level (Milliamp range currents, 0-12 VDC)

Level 2—Medium Level (28 VDC, 48 VDC)

Level 3—High Level (125 VDC Control, AC Circuits 20 amps or less)

Level 4—Power Level (Power, both LV and MV)

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Generally, Levels 2, 3, and 4 circuits may be routed in RGS, IM, or DB-PVC conduits with minimum practical installation spacing between conduits. RGS or IM routing may be used above or below grade. DB-PVC conduits may be used for below grade circuits only. Level 1 circuits are to be routed in RGS conduit above and below grade. RGS and IM conduits are to be grounded to the plant’s ground grid at both ends. Power cables are to be grounded to the plant’s ground grid at both ends. Instrumentation cables are to be grounded to the plant’s ground grid at one end only.

It is not allowed cables direct burial.

7.16.2 Medium voltage cables All medium voltage cables shall be extruded XLPE or EPR insulated with a LSF (low smoke and fume) sheath.

They shall be flame retardant as per IEC 60332 standard and waterproof.

7.16.3 Low voltage cables All low voltage cables shall be extruded XLPE insulated with a LSF sheath.

They shall be flame retardant as per IEC 60332 standard and waterproof.

7.16.4 Control and instrumentation cables All multicore control cables shall have approximately 20 per cent spare cores, but not less than two cores for future use. All cores shall be PVC or XLPE insulated, and numbered throughout their length. Individually screened twisted pairs or overall screened multicore cables shall be provided for control and instrumentation cables.

7.16.5 Telephone cables All telephone cables shall have a minimum of two pairs of tinned solid copper conductors. The minimum conductor diameter shall be 0.5mm. All telephone cables shall have color coded core insulation.

The insulation and outer sheath of telephone cables for internal use shall be halogen free.

Cables with more than six pairs shall have a fire barrier tape.

All telephone cables for external use shall have cores embedded in a water repellent gel to prevent the ingress of moisture, and an outer sheath of tough UV resistant polyethylene.

Telephone cables which are direct buried shall be armored.

7.16.6 Optical fiber cables All fiber optic cables shall comply with IEC 60794, and have Aramid type strain relief elements. The cables shall be able to operate continuously in temperatures between –10°C and +60°C.

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The fiber optic cables shall be loose tube type, with the fibers fed into tubes. The tubes shall be sufficiently strong to hold their shape and provide protection for the fibers against deformation and friction. Each tube shall be color coded.

Where fiber optic cables are to be laid in contaminated ground, a water repellent gel filling and a moisture barrier shall be applied longitudinally over the cores to ensure long term water tightness.

An inner polyethylene sheath shall contain a hydrogen scavenger to eliminate the risk of hydrogen build up around the fibers during operation.

Fiber optic cables which are direct buried shall be armored.

7.16.7 High temperature cables Silicon insulated cables shall be used for applications such as instrumentation, alarms, lighting, and essential services in temperatures between –60°C up to (200°C) such as for the interconnections to the gas turbine compartment. Stranded conductors shall be to BS 6360/VDE 0295 Class 5. A glass fiber braid shall be applied over the silicon insulation, with a silicon outer sheath. Where mechanical protection is required, a glass fiber tape shall be applied over the silicon sheath with an outer galvanized steel wire braid.

7.16.8 Intrinsically safe cables Cables used for intrinsically safe circuits shall have a blue outer sheath in accordance with IEC 60079-14. No other cables shall be supplied with a blue outer sheath.

7.16.9 Cable installation All cables shall be laid in preformed trenches, in ducts, and supported on racks and trays.

Buried unarmored cables shall be mechanically protected throughout by ducts encased in concrete.

Cable trays, ladder racks and supports shall generally be heavy duty hot dipped galvanized mild steel. Stainless steel or GRP shall be used in saline atmospheres.

To enable complete redundancy to be maintained, two separate routes shall be used for the data highway.

The cabling systems of each unit shall be physically separated, or segregated by fire barriers with a minimum of 1 hour fire resistance.

Preformed trenches shall be of adequate size to allow for cable trays or ladder racks to be installed on the side of the trenches. The trenches shall be complete with concrete covers.

Cables laid direct in the ground shall be covered with a layer of sand, with protective tiles above the sand. Tape shall be laid above the tiles to indicate the presence of cables below. However, direct burial is not preferred, proposal for such installation method except for street lighting will require MoE’s approval.

Draw pits shall be positioned at reasonable intervals in long runs and changes of direction of cable ducts.

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Cables rising out of a duct or the ground shall be protected for a minimum of 1.5 m above the finished floor level.

Cables shall be supported and affixed on cable trays at regular intervals. Ladder rack shall be used for power and control cables with a diameter larger than 15 mm.

Control cables shall not be run on the same tray or ladder as power cables.

Single core cables run in trefoil shall be cleated using non magnetic trefoil clamps which shall be capable of withstanding the forces produced under short circuit conditions.

Steel cable clamp ties shall be used for vertical runs of cable. PVC and nylon tie wraps shall not be used on horizontal runs which are in direct sunlight.

PVC shrouds shall be provided over all cable glands.

Cable lugs shall be of the double compression type.

Metallic removable covers shall be provided for trays and ladder rack where the cables are in direct sunlight.

Cores of all control cables shall be long enough to allow a second termination at a future date.

Screens on multicore cables shall be insulated from field instruments and cable armour and shall be connected to ensure continuity throughout their length.

All cables and cable cores shall be unambiguously identified.

All MV cable terminations shall be complete with pot type seals, cold compound, glands, and high temperature neoprene sleeves.

Wiring ferrules shall be suitable for affixing to the cable cores.

All steel conduits along with all accessories and fixings shall comply with IEC 60423 and IEC 60614. Minimum conduit size shall be 20 mm2. Conduit shall be hot dip galvanized; fittings shall be galvanized malleable iron.

All ducts and conduits shall have their ends sealed against the ingress of water and oil.

Conduits and ducts shall be sized to enable the cables to be easily drawn in.

Cable trunking shall be manufactured from galvanized mild steel. The coating shall comply with ISO 1461.

The trunking shall be provided with removable covers.

Copper bonding links or continuous copper earth conductors shall be fitted across all trunking joints.



Where cables pass horizontally through walls or vertically through walls, rooms, floors and ceilings non-combustible, non-metallic fire barriers and fire stoppers of approved design for two hour rating shall be installed.

7.16.10 Electrical equipment for hazardous areas The installation design, and the manufacture, certification and installation of electrical equipment in hazardous areas shall comply with IEC 60079. All hazardous areas shall be shown on site layout drawings.

7.17 Electrical building services

7.17.1 Scope of works

The scope of works for the Electrical Building services shall include the following:

a. lighting systems

b. small power systems (including for the fire protection and HVAC systems)

c. distribution system

d. cables and Wiring

e. lightning protection system.

f. Earthing system.

The Contractor shall be responsible for the complete design, detailed design calculations, equipment selection, installation, testing and commissioning and testing of the complete electrical building services systems subject to the approval of MoE and/or Owner’s Engineer.

Design calculations, system diagrams and construction drawings shall be submitted for approval. Design information shall be submitted with description of the system and all calculations as detailed in Section 10.8.2

The Contractor shall ensure that the equipment is provided suitable for the location it is to be installed in taking into account temperature and environmental conditions expected on site.

The Contractor shall include for providing all as constructed drawings, which shall be prepared as the works proceed. Completed sets of Operational and Maintenance Instructions including all test, commissioning and any other documentation required to maintain the works shall be submitted to MoE and/or Owner’s Engineer for approval.



7.17.2 Normal, external and emergency Lighting systems

7.17.2.1 Scope of works

Lighting systems shall be provided throughout the station for all areas, outbuildings and external areas to the levels required by this Specification.

The lighting system provided shall be in compliance with the Regulations, Codes and Standards and comprise normal, emergency (including operational security lighting) and external lighting systems that will include a fence security lighting system.

The mounting positions of all luminaries in all areas shall be arranged to allow maintenance to be carried out on each fitting with a minimum of labour and access equipment.

The design and installation of lighting shall be based on the following Regulations/Standards:

a. Requirements for Electrical Installations, IEE wiring regulations BS 7671 as

issued by the Institution of Electrical Engineers, London and British Standards, UK.

b. The Code for Lighting, Lighting Guides, as issued by the Chartered Institution of Building Services Engineers (CIBSE) London, UK.

All interior and exterior lighting designs shall be undertaken using computerized calculation and shall be presented using the point-by-point calculation method or flux distribution from luminaries reaching a grid of illuminance points spread across the working plane for all of the indoor and outdoor lighting.

Lighting design shall take into account efficiency, symmetry, application, operational plant, and glare, glare that might affect the CCTV cameras, computer screen environments, maintainability and long life. The CIBSE definitions and recommendations for uniformity ratio, diversity, and maintenance factor shall be applied. The Contractor shall state the assumptions applied for cleaning and relamping of luminaries and ensure that these are compatible with the normal practice being applied to the local environment. The Contractor shall design using the most economical method of achieving the maintained illuminance taking into account electricity costs and lamp replacement costs etc.

Lighting levels shall be graduated as required for comfort, safety and monitoring.

The lighting systems will consist of the following systems.

Normal lighting system 400/230 V AC serving approximately 75 per cent of the total lighting at a given area via the lighting distribution system.

The emergency lighting system 400/230V AC serving 25 per cent of the total load at a given area and connected via a lighting distribution board. Basic source of power shall be the diesel generator. The



emergency lighting system shall also be capable of illuminating all exit signs, doors, stairways, and corridors, other routes of exit and outside each fire exit together with other areas of specific risk. The emergency lighting system shall enable persons to make their way safely out of the area or premises without assistance.

Operational (high risk task area) lighting system 230 V ac connected via distribution boards for control rooms and walkways. Basic source of power shall be from an independent inverter system. For buildings remote from the inverter the exit signs and buildings shall be illuminated by self contained battery packs. This system shall be capable of 3-hour operation

Circuit design shall ensure that operation of a circuit protective device or failure of a circuit component shall result only in limited loss of illumination in a room or area.

7.17.2.2 Normal lighting

The lighting installation, shall under normal operating conditions and throughout the stations operational life be capable of providing the minimum service levels of illumination as listed below: These levels shall be based on measurements being taken after the lamps have operated for not less than 100 hours. The method of measurement is to be carried out in accordance with the International Commission of Illumination (CIE) Publication No 29. Measurements to be generally taken at floor level.

Area Description of activity Standard Maintained Luminance (lux)

Gas turbine area Operating floor 200

Substations Control areas/room 250-500

Black start/emergency Data printers 300

Diesel generator building Engineers/offices 300

Control and administration building

Monitoring room 300

Workshop and stores Mess room 200

Water treatment plant Metering room 200

Switch room 200



Area Description of activity Standard Maintained Luminance (lux)

Access corridors 150

HV equipment floors 150

Marshalling room/stairwells 150

Cable floor/cable risers 50

Battery room 150

Entrance 150

Fuel oil plant room 150

Stairwells/corridors 150

Station unit switch room 200

Workshop/store 300

C&I equipment 300

Electronics room 300

Switchgear room 200

prayer room 250

Stores 200 - 300

Chemical laboratory 300

Kitchens 300

Kitchens 500

Conference rooms 300 - 500

Locker rooms 200

Cable tunnels 50

Transformer compounds 30



If there are areas that are not included in the above BS ISO 8995 should be used for guidance.

The lighting shall be designed to provide visual performance, safety and amenity. Visual performance shall be free of excessive stroboscopic effects and flicker from discharge type lighting.

The Contractor shall take into account the expected wall, floor and ceiling reflectance values when undertaking the design calculations. The lighting designs shall also take into account the proposed equipment locations.

The Contractor shall base his design calculations on fluorescent lamps of a white colour and a colour-rendering index of typically 95. Lamps shall be triphosphour or multi-phosphor type. High frequency ballasts shall be provided in all fluorescent luminaries.

The use of low energy/compact fluorescents will be considered wherever the location and purpose of the area is suitable. The design will incorporate energy saving systems and make possible use of local isolation, movement and presence detectors wherever such a system will provide potential energy savings.

The selected luminaries shall be suitable for its application. Anti vibration dampers shall be used where required, such as at crane bay.

All normal lighting shall have uniformity levels (ratio of average to minimum) no less than 0.8. The type and quantity of fixtures and their luminous intensity shall relate to the space being illuminated and shall take into account the effect of the architectural space concept and colour scheme. Local task lighting shall be provided as required to keep open area lighting to the minimum requirement.

The selection of luminaries and requirements of illumination for various areas shall be in accordance with the recommendations published by the Illuminating Engineering Society with consideration of the safety and working conditions on the Project. The Contractors design shall reduce to a minimum the different types and sizes of luminaries used on the project and shall use wherever possible linear fluorescent luminaries surface mounted in plant locations. The use of one standard length fluorescent tube is preferred but this does not exclude using other lengths if required for design considerations.

Luminaries shall be located as far as is reasonably practicable to allow maintenance to be carried out on each luminaries with a minimum of labour and access equipment

7.17.2.3 Emergency lighting

All emergency lighting schemes shall be arranged to provide the required illumination on interruption or failure of normal lighting supply, operation of a circuit breaker or fuse or manual acts such as accidental opening of a switch controlling normal lighting facilities. The Contractor shall design, supply, install, wire and connect up a complete emergency lighting installation with a minimum of 3-hour operation, which shall be carried out in accordance with the following:



a. BS 5266, Part 1, 1999 (Code of Practice for Emergency Lighting at Premises)

b. BS EN 1838, Lighting Application – Emergency Lighting.

This shall include the provision of a 230 V AC UPS system for the operational (high risk task area) lighting system areas. The Contractor shall design for dedicated UPS units that are to be for emergency lighting use only.

Emergency lighting including operational (high risk task area) lighting system shall be supplied to all areas.

The emergency lighting system shall consist of the following types of fittings:

a. non-maintained 230 V AC

b. maintained 230 V AC

Emergency lighting (operational (high risk task area) lighting system) fed by the dedicated UPS system

- Fluorescent luminaries, operational areas 15 lux at floor level Non-maintained

- Fluorescent luminaries or high bay metal halide discharge luminaires with auxiliary lamp for instant illumination inside the electrical operational rooms. 15 lux at floor level Non-maintained

- Fluorescent luminaires inside switchboard/electronics rooms to serve as standby lighting 100 lux at floor level Maintained

- Illuminated exit signs of all final exit doors (non UPS supply) Maintained, self-contained battery back up bulkheads

- High bay metal halide discharge luminaires with auxiliary lamp for instant illumination 15 lux at operating floor level) Non-maintained

- Floodlight type units mounted on the turbine/generator house side walls area. 15 lux at floor level Non-maintained

Emergency lighting on paths of egress at floor level shall have a maximum-to-minimum illumination uniformity ratio of 40 to 1, which shall not be exceeded. The emergency lighting for stairs and escalators shall emphasise illumination on the top and bottom landings and at all intermediate landings

The emergency lighting shall be arranged to come into operation automatically upon failure of the normal lighting sub-circuit failure. The UPS shall be sized to take 110 per cent of the full design load for three hours.

7.17.2.4 External lighting



The Contractor shall design supply, install wire and connect up a complete external lighting system for all areas of the development.

The detailed positioning of all lighting points to achieve the illumination levels shall be subject to the approval of the Engineer and must be in uniform and symmetrical arrangement.

All lighting shall be designed to meet the requirements of lighting guide LG06: 1992. For the outdoor environment issued by the Chartered Institution of Building Services Engineers.

Illumination levels shall also be in accordance with the lux levels indicated below. Where these two contradict the more onerous shall take precedence. Where a range of average illuminances are recommended in the guide for a particular application, the Contractor shall design his lighting scheme to provide an illuminance not less than midway between the recommended upper and lower valves.

Transformer area 100 lux Fluorescent

Operating plant areas:

Machinery areas 200 lux Metal Halide

Platforms/ladders (active) 50 lux HP Sodium

Walkways 50 lux HP SODIUM

Road, platform/ladders (inactive), 30 lux HP Sodium

The security fence shall be continuously illuminated during hours of darkness by linear low-pressure sodium lighting to provide an even vertical illuminance of 25 lux on the face of the fence.

These low mounted glare lights will allow the security patrol personnel to view the surveyed field, the area outside the fence is so that persons outside of the fence cannot view a guard inside the project site boundary. This shall be undertaken utilizing luminaires installed on 3 m high hot dipped galvanized columns

When lighting tower/columns are required, these shall be complete with luminaries’ mounted at suitable heights in accordance with design calculations and at suitable mounting locations. Lamp replacement shall be possible easily.

All external doors of buildings shall have external luminaires installed adjacent to the doors to provide illumination immediately outside entrances. This is in addition to any other external or roadway lighting.

7.17.2.5 Related Standards



a. IEC 60364 Electrical Installations of Buildings

b. IEC 60064 Specification for tungsten filament lamps for general service (BS 161) (batch testing).

c. BS 5649 Steel columns for street lighting

d. BS EN 60598 Luminaires

(BS 4533)

Pt 1 General requirements and tests

Pt 2 Detail requirements

e. BSEN 60081 Tubular fluorescent lamps for general lighting service. (BS 1853)

f. BSEN 60921 Specification for ballast for tubular fluorescent lamps. (BS 2818)

g. IEC 60188 High-pressure mercury vapour lamps

h. BSEN 62035 (excluding Fluorescent Lamps) (BS 3677)

i. IEC 60662 High-pressure sodium lamps (BS 6193)

j. BS 3871 Miniature and moulded case circuit-breakers

k. BS 4782 Ballasts for discharge lamps (excluding ballasts for tubular fluorescent lamps)

l. IEC 60947 Low-voltage switchgear and control gear m. Codes for Interior and exterior lighting (Chartered Institute of Building Services Engineers.)

7.17.2.6 Materials

Luminaires

A list of proposed luminaires is shown below. However, this list shall not be regarded as complete until the design stage is finalized. The luminaire specification shall be produced ensuring that the equipment ordered is of the latest design, quality and shall be suitable for its final location.

Luminaires used indoors shall be minimum IP 21 protection and for external use IP 65 The types of luminaires shall be as follows:



a. Recessed fluorescent luminaries with prismatic diffuser, type GE 5500/51/414 T5 or equivalent.

b. Single lamp, circular luminaire with opal diffuser, Type GE Brio 38W or equivalent

c. Surface mounted fluorescent luminaries Type GE Series 5506/404 T5 or equivalent.

d. Floodlight with mounting bracket, Type GE PFE 400 or equivalent.

e. Indoors area, high bay ceiling or pendant mounted light luminaire, Type GE Eurobay 400 W CMH or equivalent.

f. Weatherproof bulkhead fitting for SON lamp, type GE WL-70 or equivalent.

g. High bay metal halide discharge luminaire with c/w auxiliary lamp for instant

illumination (200 lux). Type GE Eurobay 400 W CMH CD Option or equivalent.

h. Non-maintained 230 V ac twin floodlight type luminaires (15 lux).

i. Non-maintained bulkheads (15 lux).

j. Maintained, self-contained bulkheads (for EXIT illuminated signs). The final exit signs shall not be fed by the UPS system but from the normal lighting with unswitched conductors.

7.17.2.7 Switches

Switch types shall include single or multi-pole, one way, two-way and intermediate with or without pilot lamps, as may be required for each application.

All areas shall be individually switched with two ways and intermediate switching provided where necessary if there is more than one method of access and for walkways and stairways.

Luminaries installed on different floor levels or at different task locations to be controlled by their own switches. Light switches for indoor use shall be the quiet rocker-dolly type of thermoplastic material flash or surface mounting, with the degree of protection suitable to the environmental conditions of the specific area of the substation.

Where required by the design push buttons shall be provided for the control of large open area lighting installations. Push buttons shall be positive action, spring loaded having a ‘stay put' contact action with push to close and push to open action. Push buttons shall be 15 A rated at and shall have chromium plated steel cover plates.

All cover plates for lighting control switches shall be chromium-plated steel.



7.17.2.8 Lighting contactors

Contactors controlling outgoing circuits shall be located within the local distribution board and shall be rated for ‘continuous load' condition. Contactors located within the boards do not require a separate enclosure but the construction of the contactor shall be such that it is not possible to come into contact with any live parts. The operating coil shall be suitable for operation at 230 volts 50 Hz single phase.

7.17.2.9 Workmanship

The mounting height of luminaires shall not be lower than 2.4 m unless restricted by the available mounting height or if otherwise approved. The Contractor shall include all the brackets, supports and fixings, which may be required. Where provided, supports and brackets shall be hot dip galvanized and given an additional coat of epoxy paint.

All fluorescent fittings are required to strike successfully at 85 per cent nominal volts and not to extinguish at 70 per cent nominal volts.

All discharge lamps shall have an operating power factor of not less than 0.85.

7.17.2.10 Lamps and tubes

Lamps and tubes installed in the luminaires shall be of approved manufacture and of the correct type, voltage and rating specified in accordance with the related standard.

Fluorescent lamps shall be cool daylight with a minimum life of 7500 hours. High-pressure sodium discharge lamps shall be colour corrected deluxe white with a minimum lamp life of 24 000 hours operation with the required ballasts. Preferred Manufacturer GE Lighting.

7.17.2.11 Lighting and control switches

Local switches shall generally control the lighting. Separate switches shall also be provided for local lighting for panels etc and comply with the related Standard. In the central control room the fluorescent lighting shall be provided with "dimming" control to give a graded reduction in lighting levels

In large, areas, such as the turbine house, luminaries for access and inspection lighting shall be switched by contactors controlled by a switch adjacent to the plant covered by a specific load centre.

The design of general and local lighting control shall comply with the following requirements:



a. Not more than ten lighting points to be connected to and final sub-circuit.

b. Two way switches with intermediate where necessary, to be provided for lighting

in areas with more than one access, walkways and stairways.

c. Luminaires installed on different floor levels or at different task locations to be controlled by local switches.

Emergency lighting shall be automatically energized on failure of the electrical supply to normal lighting in the relevant area.

Lighting switches shall be selected in accordance with the ON/OFF control requirements of the lighting load and rated for 230 V AC single-phase operations with minimum capacity of 2500 W.

All switches shall be mounted at 1.5 metres above finished floor or platform levels. The switches shall be positioned such that they can be easily located and accessed for use.

The external lighting installation shall be contactor controlled using photoelectric cells or motorised timer.

7.17.3 Small power installation


The station and any ancillary areas shall be provided equipped with socket outlets, connection units and isolators to suit the purpose of each building or area. These outlets will be suitable for providing power supplies to all portable equipment, hand tools, portable lamps and fixed equipment required for operating and maintaining the systems

For office areas, equipment and control rooms, maintenance and testing areas or similar, the socket outlet layout shall be designed so as to effectively cover work areas with a 3 metre flexible cable. Socket layout design for all other areas shall give effective cover with a 15 metre portable extension. 110 V socket outlets shall be provided in plant areas to supply power for hand tools etc used for maintenance. The Contractor shall design supply and install a complete small power installation which shall comprise of 230 V/13 A socket outlets, 400 V/200 A oil filtration sockets,

400 V/63 a welding sockets, industrial outlets for plant areas 230 V/15 A (BS EN 60309) and 13 A fused connection units and isolators for various items of fixed appliances.

The 230 V sockets shall be wired as ring main circuits whilst 400 V sockets shall be wired as ring/radial circuits the 230 V switched 13 A socket outlets shall be flush mounted in offices and office type areas.



7.17.3.2 230V power sockets

A 13 A 230 V socket outlet system (2 pole plus earth) will be provided for offices areas, main plant areas, store areas, equipment and control rooms. This installation will be of the surface/concealed type and will be designed to provide to effective cover to all work areas with a 3 metre flexible cable. The Contract shall provide sufficient sockets for general purposes in all operational areas.

Single-phase socket outlets – 15 A. Single phase 230 V, 15 A socket outlets, connected to the normal power supply shall be of the two gang, 3-pin type in accordance with BS EN 60309.

Socket outlet installations for plant room areas shall be surface mounted and shall be located to provide effective cover with a 15 metre portable extension lead. Socket outlets rated at 15 A, 230 V single phase shall be provided for all fixed items of equipment such as small local water heaters and extractor fans etc.

A RCBO rated to trip at 30 mA at the local distribution board shall protect each small powers ring main or radial circuits.

7.17.3.3 230V power accessories

Cooker control units shall be provided for kitchen cooking stoves consisting of a 45 amp, double pole main switch with pilot lamp and a connector unit complete with terminal blocks, cable clamps and cover plate.

Water heater switches shall be rated 15 amp, 20 amp or 45 amp depending on load requirements with red pilot lamp and switch plate engraved ‘Water Heater'. Hand dryer switches shall be rated 15 amp with red pilot lamp and switch plate engraved ‘Hand Dryer'.

7.17.3.4 400 V socket outlets

Power socket outlets shall be rated at either 16 A, 32 A, 63 A or 200 A and shall have 4 pole connections and two earth connections.

The Contractor shall provide socket outlets in all oil filled transformers compounds for the connection of a mobile oil purification plant. The socket outlets shall be located so that the mobile oil purification plant can be positioned in front of each transformer bay using a maximum cable length of 20 metres.

The Contractor shall supply and install welding socket outlets complete with plugs at strategic points located on a nominal 50 metre grid so that all parts of the Plant can be reached using a maximum cable length of 35 metres. The socket outlets shall be 400 V, 63 A, three phase, neutral and earth to BS EN 60309. They shall incorporate an on-load disconnector, mcb rated to suit the switch and a residual current circuit device (RCBO) rated at 30 mA.



7.17.3.5 9.7.3.6 Related Standards

a. IEC 60364-5-54 Earthing arrangements and protective conductors for indoor installations up to 1000 V ac and 1500 V dc

b. BS 1363 13 A plugs, socket outlets, adapters and connection units switched and un-switched 13A socket outlets and boxes

c. BS 4343/IEC 309 Specification for industrial plugs socket outlets and couplers for ac and dc supplies.

d. BSEN 60309 Plug and socket outlets

e. IEC 60309 Plugs, socket-outlets and couplers for industrial purposes

f. BS 3871 Miniature and moulded case circuit-breakers.

7.17.3.6 Material

Socket outlets shall be metalclad to IP67, watertight and incorporate a spring-return flap cover. The plug and socket shall be interlocked such that the unit cannot be switched on until the matching plug is fully inserted, nor can the plug be withdrawn with the switch closed.


The mounting height of general-purpose socket outlets and power socket outlets shall be as follows:

General-purpose socket outlets mounted in walls of rooms such as offices and control room areas shall be 300 mm above finished floor. In all other maintenance type areas, equipment or station areas the mounting height shall be 600 mm above finished floor.

Power socket outlets shall be mounted 1.2 metres above finished floor. MoE and/or Owner’s Engineer at site shall approve the position of all socket outlets before installation work is commenced

7.17.4 Distribution system


Sub distribution boards shall be provided for the lighting and small power supplies throughout the station. A unique code number shall designate to them and all drawings and diagrams.



The boards shall be 400/230 V ac 3 phase and neutral, generally grouped together where suitable, within a free standing floor mounted totally enclosed cellular cubicle type switchboard or as individual boards where required. Each board shall be equipped with main incomer and sub-main circuit breakers.

The design shall ensure that all equipment is provided that will take the expected symmetrical fault rating and shall be capable of breaking rated load current. Lighting and small power final sub-circuits shall be supplied from ways protected by miniature circuit breakers. A minimum of 20 per cent of each type and rating of MCB/RCCD ways shall be provided as spares.

7.17.4.2 Related Standards

a. S 5486 Pt 12 and 13 Miniature Circuit Breaker Boards.

b. IEC 60947 Distribution boards and all components.

c. BS 5419 and BS 3871 Air break switches, disconnector and MCCB's.

7.17.4.3 Material

Sub-main circuit breakers shall be of the moulded case plug-in and bolted type selected in accordance with the load served and to withstand the actual fault levels at the bus bars. Miniature circuit breakers of the residual current earth leakage type shall be used for socket outlet feeds and some small power supplies.

Sub-distribution boards combining lighting circuits and socket outlet circuits shall be electrically separated by the provision of separate bus bars and the socket outlet section shall be protected by RCBO.

The emergency lighting shall be operated (i.e. switched on due to ac failure) when the voltage of any one phase drops to 80 per cent of normal supply voltage.

The relay shall be able to detect when the 400 V ac supply voltage has fallen to 80 per cent for half a cycle and to energize the emergency lighting within 0.5 seconds. Upon restoration of normal ac supplies a suitable delay shall occur before the emergency lighting are switched off. A timer linked to the low voltage relay shall provide this function but shall not be included where fluorescent tubes are used for the ac lighting. The low voltage relay shall be equipped with a manual override to provide a lamp test facility for the emergency lighting or switch it on manually should the automatic system fail.


Distribution boards shall have an enclosure of zinc coated or galvanized steel of minimum thickness of 1.8 mm, having a hinged door with padlocking.



Enclosures shall have a degree of protection to IP 20 for office type rooms (indoor locations) IP 44 for indoor locations in plant areas and IP 65 for outdoors and damp situations.

Access doors shall open 120° without obstruction to give access for operation of switches for MCB and RCD’s. The local distribution boards shall be generally mounted at 1450 mm above ground level with a clear working space of 1000mmfor operation testing and maintenance.

Gland plates shall be fitted to both top and bottom for cable entries to incoming and outgoing circuits and allow for spare capacity

7.17.5 Cables and wiring See Chapter 7


The supply and erection of all LV power cables; control cables and wiring, complete with accessories shall be provided as described in chapter 7.


Lighting suspension trunking shall be manufactured from heavy gauge sheet steel with a galvanized finish complying with the related Standard. Trunking shall be complete with all manufactured standard couplings, bends, tees, cable retainers, stirrup suspension, hangers and fixing brackets and all other accessories as required.

Self-tapping screws shall not be used in the trunking assembly and the inner surface of the trunking shall have a smooth finish.

All conduits terminating at the trunking shall be bonded together and to the trunking. The trunking shall not form part of the earth continuity conductor and separate earth conductor shall be provided in the trunking. Copper earth bonding links shall be fitted across all joints.

Lighting trunking shall be used exclusively for the purpose of lighting fitting suspension and the routing of directly related wiring.

7.17.5.3 Conduit

The conduits shall be continuous from outlet to outlet to distribution boards, junction or pull boxes and secured to all boxes so that each system is electrically continuous from service to outlet.



7.17.6 Lightning protection system


The Contractor shall provide and install a lightning protection system to provide the necessary protection to each building and each equipment as required in specifications. Each building shall have its own air terminal network, down coming tapes and earth points. For the Power Island the design criteria shall follow the GE specified lightning protection system.

The lightning protection system shall be designed, furnished and installed in accordance with the latest applicable NFPA Standard 780, ANSI/UL Standard 96A, BS 6651 and components BS EN 50164 and any other applicable codes and standards.

The Contractor shall connect the lightning rods directly to the earthing system specified in chapter 7.


Joints between lightning protection conductors shall be accessible without disturbing the roof structure, no joints located below roof finish will be accepted.

At ground level the down conductor terminates shall terminate at a brass test clamp mounted at 1500 mm above finished floor level. There shall be minimum two such ground paths.

The earth electrode shall comprise as a minimum required numbers of 3000 mm, 20 mm diameter, hard drawn solid copper ground rods, screw coupled. See Section 7.15 for ground testing requirements. Final connection to the electrode rod shall be by a pressure type clamp connection or exothermic welded. Lightning system shall be connected to the plant earthing system. It shall be possible to measure ground and lightning system resistances separately.

The complete installation shall be tested in accordance with the relevant Standards. The Contractor shall provide the MoE and/or Owner’s Engineer with copies of the test certificate produced for the lightning protection system.

Surge arrestors to be fitted for protection against transient surge’s that occur during lightning strikes

7.17.6.3 Bonding e Contractor shall include for bonding all items of exposed extraneous metalwork, i.e. masts, AHUs etc and louvres, to the lightning protection system.

A separate electronic earthing system shall be installed as per the latest Codes and Standards for all electronic and communication systems. This system shall be separate from the plant protective bonding system.



The Building Services systems shall all be bonded to the nearest earthing point distribution bar normally located within the electrical equipment rooms. The earthing arrangement and protective conductor system shall be in accordance with the BS 7671 Requirements for Electrical Installations



ANNEX 1: Generator Step-up Transformer

Scope of supply

The scope of supply consists of:

a. 2 (two) winding Generator Step-Up Transformers each 160 MVA; 400 kV/15kV

b. 1 (one) insulating oil treatment plant

General requirements

All the Generator Step-Up transformers shall be oil filled core type, GE or equivalent.

Transformers shall be in designed and constructed in accordance to IEC60076-1, -2, -3, -5, -10, IEC 60354 , IEC 60214 and fulfill all the requirements from relevant IEC standards applicable.

The Generator Step-Up transformers shall be for outdoor installation.

Equipment shall be ultimately suitable for use and provided with higher value parameters if found required per design and system calculations.

Tank and metallic parts: Tanks and metallic parts shall withstand 25% greater than the maximum operating pressure. Tank shall be suitable for full vacuum. Tank inside shall be painted white. Tank top shall use anti skid type paint. Fully assembled oil filled unit shall be suitable for jacking, lifting, skidding and rolling. Four (4) stainless steel 100x75x20mm two hole grounding pads shall be provided at bottom corners suitable for 240mm2 copper cable connection. Separate pad for neutral grounding shall be provided at base level. Insulated copper shall be used for connection from neutral terminal to the pad.

All valves as required per IEC recommendation including drain, filter, sampling, filling, isolating etc. shall be provided of brass or bronze with open/close indication, provision for pad locking. Drain valves shall have sampling valve located on tank side of the drain valve. Oil shall be possible to drain to less than 25 mm level. Pressure relief valves and isolation valves on both sides of Buchholz relay shall be provided. The conservator shutoff valve and the main tank shutoff valve must be ball valves.

Nitrile or cork-neoprene type gaskets shall be provided in grooves with metal stops to prevent over compression.

Core clamping arrangement shall be equipped with core and coil lifting eyes. Core shall be grain oriented type and meet the criteria –

for IZ = 10 % or greater, MFD = 1.725 – (IZ – 10) (0.0093) Tesla. where MFD = Maximum flux density at 100% no-load voltage at any tap position, For IZ below 10% use MFD = 1.725 Tesla, IZ = % impedance at maximum rating at rated tap.



Core shall be grounded with a removable test connection accessible from a manhole. For each core, a ground lead shall be brought out through an appropriate bushing and grounded to the transformer tank. The bushing and core ground connection shall be installed in a suitable box to protect the bushing and the core ground.

Copper windings shall be suitably clamped by mechanical means at the top and bottom to prevent shifting under short circuit conditions. All windings subject to inward radial buckling shall be designed to withstand “free” or unsupported buckling in addition to forced or supported buckling. At the design review, the calculated free buckling and the withstand values shall be presented. The control of inward radial forces shall not depend upon bracing to the core. Epoxy bonded conductors for the inner and outer windings are preferred and will be a design review item. Zero system impedance shall be used.

Conservator shall be provided with a weatherproof ventilator with drain valve. Conservator shall be designed to withstand full vacuum and provisions shall be made for the filling of the main tank and conservator while under vacuum.

Control cabinets shall be weather protected IP-55 or better with hinged door using stainless steel hinge pin. All cable entries shall be from bottom. Necessary controls shall be provided. Selection shall be possible for Local or Remote from the tap changer panel. A remote tap position indicator panel shall be provided also. Local or remote tap Raise or Lower operation shall be possible. All safety interlocks, alarm, indications, trips shall be provided as required for local and remote.

The transformers equipped with off load tap changer shall include provisions for padlocking and tripping in the event of inadvertent operation of the tap changer while transformer is energized.

The insulating oil treatment plant shall be able to clean not less than 6,000l/h and it shall be equipped with redundant vacuum pump.

Transformer shall be suitable for bidirectional power flow. All windings of the transformer shall be capable of withstanding short circuit for IEC specified duration of time when operating at any tap position including the one that correspond to lowest effective impedance, with fault maintained at the terminals. It shall be considered as if rated full voltage will be maintained on one side of the transformer while the short circuit happens on the other side. Contractor shall demonstrate such capability in accordance with IEC 70076-5.

160 MVA Generator Step-Up transformers required data:

POWER TRANSFORMERS UNIT REQUIRED DATA

1 Rated power with ONAF cooling at site condition MVA 160

2 Rated power with ONAN cooling at site condition MVA 120




3 Type designation

4 Two winding three phase oil immersed Yes

5 Rated voltage ratio kV 15/ 400± 5 X 2.5%

6 Rated frequency Hz 50

7 Vector group Ynd11

8 Cooling ONAF

9 Method of earthing Effectively earthed in HV side

10 Type (graded/non graded) of windings:

HV windings

LV windings

graded

non graded

11 Rated voltage of windings

HV windings

LV windings

kV

kV

400kV

15kV

12 Highest voltage for the equipment

HV windings

LV windings

kV

kV

420

17.5

13 Rated power frequency withstand voltage at:

HV windings

LV windings

kV

kV

630

95

14

Rated lightning impulse

HV windings

LV windings

kV

kV

1425

125




14A

14B

14C

Rated switching impulse withstand votage

HV windings

LV windings

ACLD test with PD measurement

Test voltage U1 to IEC 60076-3

Test voltage U2 to IEC 60076-3

Maximum PD level at U2

Chopped wave lightning impulse Routine test

Zero sequence impedance measurement type test

Determination of sound levels Type test

Determination of capacitance Type test – between windings, winding -earth

kV

kV

kV

kV

pC

1050

Transferred from HV

412

364

500

Yes

Yes

Yes

Yes

15 Maximum temperature rise at rated power at:

Windings

Hot spot of windings

Top oil

°C

°C

°C

55

68

50

16 Losses:

Iron losses

Copper losses

kW

kW

Indicate for guarantee and evaluation

Indicate for guarantee and evaluation

17 Tap changer type: Off-load (on HV side)




Tap number: ±5x2.5%

18 Symmetrical short circuit withstand current (duration 1 second):

HV windings

LV windings

kA

kA

40

40

19 Short-circuit impedance at rated frequency

(referred to 160MVA and 400 kV)

p.u. 0.125

20 Terminal connection:

HV side

LV side

Bushing

Bus duct

21 Number of coolers:

number of coolers per transformers

number of stand-by coolers

8

2

22 Insulating oil:

manufacturer

type

standard

Shell

Diala B

IEC 60629

23 Type of dehydrating breather Silica-gel automatic recharge

24 Conservator

Minimum volume of conservator between highest and lowest level as percentage of total cold oil volume of transformer

% 10

25 Supply voltage for transformer:




25A

25B

25C

25D

25E

25F

Auxiliaries

Control & Protection

Current Transformers

HV

LV

Transformer gas and moisture in oil Monitoring System

Hot spot temperature Monitoring System

Over voltage detection Monitoring System

Variation of bushing capacitance Monitoring System

Spare parts

V

V

380/220AC

110DC

Refer to oneline diagram

Refer to oneline diagram

Yes

Yes

Yes

Yes

Yes

26 Manufacturer quality assurance, according to ISO 9000, 9001, 9002 and 9003

Yes

27 Type test certificate to be issued by an independent laboratory.

Yes

END OF SECTION 1V – CHAPTER 7

attachment #2. technical specification for electrical

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