This document provides information about transformers, including power and distribution transformers. It discusses core types, windings, cooling systems, installation locations, voltage ratings, and capacities. The document compares power and distribution transformers and describes their different parts. It also outlines the design process for transformers, listing specifications, calculations, and performance testing according to IEC standards.

3. Transformer
Distribution
Core type
Straight cut Angular cut
Shell type
Power
ONAN(Oil natural Air natural)
Categorizing
the transformer
production at GEMCO

4. Comparison between power & distribution transformer
Power
Transformer
Distribution
Transformer

5. Power transformer Distribution
transformer
 Installation
 Connection
 Capacity
 Voltage rating
• Cooling system
At substation
(generation side).
Δ- Δ or Y- Δ, 3 wire.
MVA.
Usually stepped
down to 11kv.
ONAF, OFAF,
ONWF, OFWF
At distribution and
transmission
(consumer side).
Δ-Y, 4wire.
KVA.
Usually stepped
down from 11kv to
415v.
Usually ONAN.
Comparison between power & distribution transformer

6. Primary Distribution Transformer’s parts
r
Rod Gap Arrester

7. Core type transformer
Transformer type
Winding
Core

8. Comparison between core & shell type transformer
The advantages of each type are:
core-type (or three limbs) is the most commonly used method
of construction, the smaller core means less weight and expense.
shell-type (or five limbs) is used for larger transformers
because of a reduced height and better mechanical protection to
the winding because it is surrounded by core.
From a manufacturing standpoint, core-type & shell-type
designs are very similar.

9. Transformer Core type

10. Angular Straight
Performance  Reduce reluctance against the
magnetic flux by reducing the
gaps between sheets. Hence
lessen the iron loss and
betters the performance.
 Provides more reluctance
to magnetic flux due to
more number of gaps. So
performance is well below
angular.
Cost  Cost is more as huge amount
of core is wasted due to the
cutting off at corner to make
it angular.
 Cost is well below the
angular cut.
Preference  Preferred where efficiency is
vital.
 Mostly used due to the
less cost.
Comparison between core & shell type transformer

11. I ) Transformers:
Power Transformer, 3 Phase, 33/11KV, 1 MVA to 5 MVA
Distribution Transformer, 3 Phase, 33/0.415 KV, 100 KVA to 250 KVA
Distribution Transformer, 3 Phase, 11/0.415 KV, 50 KVA to 500 KVA
Distribution Transformer, 1 Phase, 6.35/0.24 KV, 5 KVA to 50 KVA
Distribution Transformer, 1 Phase, 11/0.24 KV, 15 KVA to 25 KVA
Apart from these, other rated transformer could manufactured as
per requirements of clients up to 5MVA
II)Repair & Miscellaneous Works:
Damaged Distribution & Power Transformers up to 20 MVA
Products / Services:

12. Process flow diagram
PPM
•Design product
•Estimate cost
CPL
•Test raw materials
•Report
Plant
•Electrical
•Mechanical
Testing
•Test completed transformer
•Report

13. Name of Raw Materials Specification of materials
CRGO Silicon Steel Sheet Grade M-5 (width 0.3mm, density-
7.65kg/dm3, Core loss 0.97-1.39 for 1.5-1.7T)
Copper Strips Electrolytic Copper of 99.9% purity
Super Enameled Copper
Wire
SWG -14 to 21 Copper of 99.9%
purity
Mild Steel Sheet Prime Quality
HT Insulator Electrical Porcelain Insulator
Transformer Oil As per IEC-296 Class-1
Insulated Paper & Board Electrical Grade 100%
Sulphate/Kraft Pulp

14. Raw material specification
 LT Coil dimension,
Thickness=5.6mm, width=11.2mm, insulation=.45mm,
density=61.92x10^-6 kg/m3
 HT coil type- SWG17 , supper enameled
dia-1.42-1.53, density= 8.9x10^-6 kg/m3
 CRGO Silicon Electrical Steel Sheet with thickness 0.3mm
&flux density Bm≤1.7Wb/m²
IEC Standard:
 76
Vector group:
 DYN-11
Design specification

15. The design is usually 6 step core section with Cylindrical coils
In design calculation
Design specification

16. Summarizing the design:
•Specification of the transformer to be designed
•Chose Ez, Bm,
•Calculate Area and Diameter for core
•Find conductor size of HT & LT winding and calculate
current density
•Choose layout of windings-- numbers of turns per layer ,
numbers of layers, distance between coils
•Calculate R, X, Z.
•Calculation of performance
•Designing the tank

17. Transformer leg

18. Active Part
Tapping
Core
Insulation
Board
Insulation
Paper over
winding

19. Each transformer undergoes following routine tests
as per IEC 60076 requirements:
•Di-electric strength test of transformer oil.
•Measurement of Insulation Resistance.
•High Voltage Test.
•Induced Over Voltage Test.
•Ratio Test.
•Vector Group Test.
•Measurement of No-Load Loss and Excitation Current.
•Measurement of Load-Loss and Impedance Voltage.
•Measurement of Winding Resistance.
•Temperature Rise Test.
Testing