SUMMER TRAINING SEMINAR ON 220KV SUBSTATION, MURADNAGAR

-ASHISH KR. DIXIT

EN –E/4TH YR1002721028

CONTENTS INTRODUCTION DESCRIPTION OF 220KV SUBSTATION POWER TRANSFORMERS INSTRUMENT TRANSFORMERS CIRCUIT BREAKERS BUCHOLZ RELAY ISOLATORS INSULATORS LIGHTNING ARRESTERS WAVE TRAP CONTROL ROOM PLCC CONCLUSION

Substation:- A substation is a subsidiary station of

an electricity transmission, & distribution system where voltage is transformed to high to low or the reverse using transformers.

A substation generally have switching, protection, & control equipment & one or more transformers.

Types:-(a)Transmission substation(b)Distribution substation

GENERAL DISCUSSION

DESCRIPTION OF 220KV SUBSTATION, MURADNAGAR The 220KV power substation has the

capacity-(2*160MVA+1*100MVA). It receives three 220kv lines from

Sikandrabad, Loni and Dadri and two 400kv lines from Modipuram (circuit 1) and a newly installed circuit 2. It steps down this supply to 132kv, 66kv, 33kv and 11kv. 132kv line gives supply to Lalkuan, Morta, Newari, Modisteel, Hapur and Dasna, 33kv line to Rawli, Noorpur, Goelispat, and 11kv to New substation.

400kv incomer

220 kv incoming feeder 132 kv outgoing feeder

incomer

outgoing

220 KV INCOMING LINES THROUGH L.A AND CONNECTEDTO THE INSULATED DISCS

POWER TRANSFORMERS

Transformer is a static machine, which transforms the potential of alternating current at same frequency. It means the transformer transforms the low voltage into high voltage & high voltage to low voltage at same frequency. It works on the principle of mutual inductance.

When the energy is transformed to a higher voltage, the transformer is called step up transformer and then it is transmitted at lower voltage it is called step down transformer.

There are 3 transformers in the substation: 160MVA, 220/132 KV (2nos.) 100 MVA TRANSFORMER(1)

160MVA 220/132 kv transformer feeding

Transformer Gantry

Transformer LA

Current Transformer(CT)

Transfer Bus

160 MVA transformers are manufactured by ADITYA and by TRM. These are the power transformers and , there efficiency is high. Primary side is star connected while secondary is delta connected. There are seventeen tapping in it. Every transformer has OLTC to change the tap for controlling voltage.

TYPES OF COOLING:AIR NATURAL COOLINGAIR BLAST COOLINGOIL NATURAL COOLINGOIL BLAST COOLING etc.

INSTRUMENT TRANSFORMERS

Instrument transformers means current transformer & voltage transformer are used in electrical power system for stepping down currents and voltages of the system for metering and protection purpose. Actually relays and meters used for protection and metering, are not designed for high currents and voltages.

C.T. is an instrument transformer used for protection & metering of high values of currents. C.T. is used for reducing a.c from higher to lower value for measurement/protection/control. There are two classes of C.T:

protective C.T measuring C.T Protective C.Ts are used for over current protection, earth fault

protection, differential protection& impedence protection, etc. Measuring C.Ts are used with ammeters, wattmeters, KV

meters & KWH meters for reducing line.

CURRENT TRANSFORMERS

Potential Transformer or Voltage Transformer are used in electrical power system for stepping down the system voltage to a safe value which can be fed to low ratings meters and relays. Commercially available relays and meters used for protection and metering, are designed for low voltage.

POTENTIAL TRANSFORMERS

Capacitive Voltage Transformer(CVT)

Current Transformer(CT)

Current Transformer(CT)

CONSERVATOR

AIR BLAST

POTENTIAL TRANSFORMERPOTENTIAL TRANSFORMER

CIRCUIT BREAKERS A circuit breaker is equipment, which can open or close

a circuit under normal as well as fault condition. These

circuit breaker breaks for a fault which can damage

other instrument in the station. It is so designed that it

can be operated manually (or by remote control) under

normal conditions and automatically under fault

condition. Whenever a fault occurs trip coil gets

energized, the moving contacts are pulled by some

mechanism & therefore the circuit is opened or circuit

breaks.

Polycon Insulator

132KV CB

CIRCUIT BRAEKER

Circuit Breaker

ISOLATORS In Sub-Station, it is often desired to disconnect a part of the system

for general maintenance and repairs. This is accomplished by an

isolating switch or isolator. An isolator is essentially a knife Switch

and is design to often open a circuit under no load, in other words,

isolator Switches are operate only when the line is which they are

connected carry no load. For example, consider that the isolator are

connected on both side of a cut breaker, if the isolators are to be

opened, the C.B. must be opened first. If an isolator is opened

carelessly, when carrying high current the resulting arc easily  causes

flashover to earth.

Isolators

Isolators

SEQUENCE OF STEPS FOR ATTENDING MAINTENANCE:

1.Open CB on no load or full load

2.Open the isolator on no load

3.Close the earth switch

SEQUENCE OF STEPS FOR KEPT IN SERVICE

1.Open the earth switch

2.Close the isolator

3.Close the CB

Definition:- Buchholz relay is a gas actuated relay. It can only be fitted to the transformers equipped with conservator tanks as it is installed in b/w the conservator tank and the main tank i.e., the pipe connecting the two.

Principle:- Whenever a fault occurs inside the transformers, the oil of the tank gets overheated and gases are generated.

The heat generated by the high local current causes the transformer oil to decompose and produce gas which can be used to detect the faults.

BUCHHOLZ RELAY

BUCHHOLZ RELAY PICTURE

INSULATORS

The insulator serves two purpose. They support the conductor

(or bus bar) and confine the current to the conductor. The most

commonly used material for the manufactures of insulators is

porcelain. There are several type of insulator (i.e. pine type,

suspension type , strain type ,shackle types etc.) and there used

in Sub-Station will depend upon the service requirement.

LIGHTNING ARRESTERS

Lightening arrestors with earth switch lightening arrestors after

the current transformer are used so as to protect it from

lightening i.e. from high voltage entering into it. This

lightening arrestor has an earth switch, which can directly earth

the lightening. The arrestor works at 30° to 45° angel of the

lightening making a cone. The earth switch can be operated

manually, by pulling the switch towards ground. This also helps

in breaking the line entering the station. By doing so

maintenance and repair of any instrument can be performed.

Strain type

Lightning Arrestor

SUSPENSION TYPE

WAVE TRAP Wave trap is an instrument using for trapping of the wave. The

function of this trap is that it traps the unwanted waves. Its

function is of trapping wave. Its shape is like a drum. It is

connected to the main incoming feeder so that it can trap the

waves which may be dangerous to the instruments here in the

substation. Low pass filter when power frequency currents are

passed to switch yard and high frequency signals are blocked.

It is used for communication purpose.

CONTROL ROOM

It has following control panels:

1.220 KV LINE PROTECTION PANEL

2.400/220 KV TRANSFORMER CONTROL AND RELAY PANEL

3.220 KV OUTGOING DOUBLE FEEDER CONTROL PANEL

4.FREQUENCY PANEL

5.100 MVA OLTC PANEL

6.RTU PANEL

7.BATTERY CHARGER PANEL

For exchange of dates and transfer message between grid substation,voice communication is necesarry. for this purpose high frequency carrier current is transmitted on same transmission line on which power is transmitted.

Hence such communication is called “power line communication

POWER LINE CARRIER COMMUNICATION

POWER LINE CARRIER COMMUNICATION PICTURE

THANK YOU