electrical power system design of high-rise residential

8/12/2019 Electrical Power System Design of High-Rise Residential

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ELECTRICAL POWER SYSTEMDESIGN OF HIGH-RISE

RESIDENTIAL/COMMERCIAL

CONDOMINIUM BUILDING

By: Engr. Emiliano G. Marabulas,PEE


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The development of the electrical power system

design of high-rise residential and/commercial

condominium building is long and tedious.

However, in this presentation, the development

is in summary form.


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It includes the following:

1. Review of the applicable provisions of codes,

laws, and regulations that have jurisdiction over

the electrical Installations.

A.) Philippine Electrical Code Part 2009

Most of the provisions needed are in chapter1,2,3,4, and article 6.95.


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B.) New Electrical Engineering Law

Some of the provisions needed are in sections26,31,32, and 34.

C.) National Building Code (PD 1096)

D.) Distribution Service Open Access Rules

(DSOAR) of the Energy Regulatory Commission

(ERC)

Some of the provisions needed are those forconnection point, and service drops.


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2. Coordination Works

The requirements of design shall becoordinated with the architect/owner, the

engineers involve the electric utility, and the

government agencies having jurisdiction overthe electrical works.

3. Development of the Design Criteria

These are agreements of the architect/ownerand all engineering disciplines regarding data

other the mandatory requirements of laws,

ordinances, codes, etc.


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4. Development of the Design

A.) Notes

It is assumed that the electrical engineer

knows already how to design the electrical

system of a single occupancy residential

building.

B.) Study of the Architectural drawings

This is determination whether the area, space,

location, other requirements are adequate for

the electrical equipment, devices, and

materials to be installed.


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C.) Single Line Diagram

This is a drawing which shows all the major

components of the electrical system. The

single line diagram is usually prepared after

the detailed computations. However in this

presentation, it is shown ahead so that we will

be guided where in the particular system thecomputation is referred to:


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D. Computation (Residential)

1. Sub Service Entrance per Floor

a.) Compute for the total connected load of each

unit

b.) Add the total connected load for each floor

c.) Compute for the current based on the

number of units in each floor and the demand

factor shown in Table 2.20.4.5

d.) Determine the size of subservice entrance

conductors, conduits and protective device

based on the computed current.


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2. Main Service Entrance

a.) Add the connected loads of all the units.

b.) Compute for the total current based on thetotal number of units and the demand factor

shown in Table 2.20.4.5

c.) Determine the size of the main service

entrance conductors, conduits or busduct and

a protective device based on the computed

current.


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E. Computations (Commercial)

Basically the process of computations is

similar to the computations for residential

F. Computations (Administration)

1. Lighting and Convenience Outlets

Basically the process of computations issimilar to the computation for residential


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2. Elevators (motor-generator set)

(a) Branch Circuita. Size of conductors and conduits

Current=Full load current of the motor (Table

4.30.14.4) multiplied by 140% for intermittentduty cycle [Table 4.30.2.2(e)] plus 125% of

other continuous load currents.

With this value of current, the size of conductors and conduits can be determined.


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b. Protective Device

The size of the protective device is based on

the full load current multiplied by the

percentage as shown in Table 4.30.4.2 plus

other continuous loads.


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(b) Feeder Circuit

a. Size of Conductors and ConduitsCurrent=Sum of the full load of all the motors

multiplied 140% [Table 4.30.2.2 (e)] multiplied

by demand factor based on the number of elevator motors (Table 6.20.2.4) plus 125% of

the other continuous loads

With this value of current, the size of conductors and conduits can be determined


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b. Protective Device

The rating of the protective device shall not be

greater than the protective device of the

highest noted elevator motor plus the sum of

the full load current of the remaining motor

plus other continuous loads as section

6.20.7(c).


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(b) Overcurrent Protective Device

With the horsepower rating and code letter,the protective device is determined by the

kilo-volt ampere per horsepower as shown in

Table 4.30.1.7(b)


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3. Fire Pump and Pressure Pump(a) Branch Circuit

The size of conductors and conduits

Current= Full load current multiplied by 125%with the value of current, the size of

conductors and conduits can be determined


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With the horsepower rating and code letter,

the protective device is determined by thekilo-volt ampere per horsepower as shown in

Table 4.30.1.7(b)


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Current= kilo-volt ampere x horsepower rating

horsepower of the fire pumpdivided by [square root of 3 times line to line

voltage (KV)]

With the value of current, the rating of theprotective device can be determined.

(c) Overload Protection

The power circuit shall be provided withautomatic protection against overload


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4. Other motors

Other motors shall be considered as ordinary

motors.

5. Main Service Entrance

(a) Size of conductors and conduits

The current shall consider all the demandloads of the feeders, subfeeders, and branch,

including the application of the 125%.


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With the value of current and the rating of the

protective device of the highest rated motor,

the main service entrance protective device

can be determined


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G. Computations (Voltage Drop)

With the value of current and the impedance

of each part of the circuits, the voltage drop

can be computed.

H. Computations (Short Circuit Current)

With the value of available short circuit

capacity at the area, the impedance of the

transformer, the impedance of the lines, andthe motor contributions, the short circuit

current at any point can be computed.


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J. Development of Lighting Protection System

1. Conventional

This is computing the number of air terminalsand determining the materials based on

height as per Table 2.90.3.5, grounding

electrodes, and others to complete the system


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2. Enhanced

Enhanced lightning protection system ma be

used provided it is approved by the authority

having jurisdiction or listed by an organization

that is also approved


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K. Preparation of all necessary documents

With all of the above. The plans, single line

diagram, specifications, and other documents

as required by PEC 1 2009 can be prepared.


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END

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