24kV Distribution Transformer

24 kV Distribution Transformer Specification

Metropolitan Electricity Authority

Copyright 2004 by MEA.

Thank you chairperson for an introduction.

Good morning ladies and gentlemen. Its a pleasure to be with you today.

My name is Sompong Sitthichaiyanan from Metropolitan Electricity Authority.

My work is related to underground system for ten years.

Let me share experience on System configuration and ring main unit in MEAs underground distribution system.

MEA's Power System Performance

Overview

Background

Transformer Specification

Conclusion
Picture of MEAs Transformer Single Line Diagram General Information

I have divided my presentation into four parts.

First, introduction.

Second, system configuration.

Third, ring main unit.

Final, conclusion.


Background

Picture of MEAs Transformer


With public concern on power system reliability, quality and environment in urban areas.

It is necessary to convert distribution system from overhead to underground.


Background

Single Line Diagram

24 kV

MEA Station

416/240V

Low Voltage Customer





Background

General Information
Number of Purchase
: 1,000 units / year
Service Area : 3,191.60 sq.km.





Reference Standard
IEC 60076-1(2000) :
Power Transformers Part 1 : General
Thailand Industrial Standard
TIS 384 (1992) :

Standard for Power Transformer






Test Requirement
Type Test
: Temperature Rise

: Lightning Impulse

: Short Circuit Test






Test Requirement
Routine Test
: According to Standard (All unit)

: Temperature Rise (1 Unit)

: Lightning Impulse (1 Unit)






Ratings & Features
Type of Cooling : ONAN Rated Power : 45, 75, 112.5, 150,
225, 300, 500 & 1,000 kVA
Phase : 1 or 3 phases Overhead, Outdoor & Mineral-Oil-
Filled






Ratings & Features
High voltage winding: 24 or 12/24 kV Low Voltage Winding : 416/240V Temperature Rise
: Winding < 65 K

: Top Oil < 65 K






Ratings & Features
Connection : Dyn 1 BIL : 125 kV (for 24 or 12/24 kV)
: 30 kV (for 416/240 kV)
Tap : -4 x 2.5 %





Ratings & Features
Impedance Voltage
: up to 4.4% (45-225 kVA)

: more than 6.5% (300-1,000 kVA)






General Requirement
Installation Type
: Concrete Pole for 45-300 kVA

: Platform for 500-1,000 kVA
Provided with Lightning Arrester Bolted Type Transformer Tank Cover





General Requirement
Maximum Weight
: 1,250 kg for 45-150 kVA

: 1,650 kg for 225 kVA

: 1,800 kg for 300 kVA

: 4,500 kg for 500-1,000 kVA
Average Sound Level < 48-58 dB





Tank & Cover
Constructed of Steel with
Adequate Thickness
Steel cover and electrically bonded to
Tank.






Core & Coil
Made of Grain Oriented, Low Loss,
High Permeability, Silicon Steel Strip
Not Shift in Any Direction during
Shipping & Installation






Winding
Either Copper or Aluminum Foil Type Secondary Winding Withstand Thermal & Mechanical
Effects by External Short Circuit






Accessories

up to 300 500 and up

Tap Changeryes yes

Dual Switchyes yes

Thermometerno yes

Liquid Level Gageno yes

Lifting Facilitiesyes yes

Lightning Arresteryes yes






Accessories

up to 300 500 and up

Pressure Relief Deviceno yes

Circuit Breaker yes no

Supporting Lugyes no

Sampling Valveno yes





Tap Changer

-4 x 2.5 % Rating Voltage





Dual Voltage Switch

12 kV or 24 kV

Selection





High Voltage Bushing

Bushing





Low Voltage Bushing





Bushing Cover

Bushing Cover





Thermometer





Liquid Level Gage





Lifting Facilities





Lightning Arrester





Pressure Relief Device





Circuit Breaker (CSP)





Supporting Lug

Sampling Valve

Other





Nameplate

Earthing Point






Loss (Watt) - Single Phase

kVA No LoadLoad

50145 420

75200 540

100240 700

1673201,170

3335002,340






Loss (Watt) - Three Phases

kVA No LoadLoad

45160 360

1503001,000

3004801,860

500 6703,030

1,0001,0006,400





Conclusion





Question & Answer


Any question or comment?


24kV Distribution Transformer

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