Ppt on Transformer

Categorizing the transformer production at GEMCO

Transformer

Power

Distribution

Shell type

Core type

Straight cut

Angular cut

ONAN(Oil natural Air natural)

Comparison between power & distribution transformer

Power Transformer

Distribution Transformer

Comparison between power & distribution transformer Power transformer  Installation

At substation (generation side).

 Connection

Δ- Δ or Y- Δ, 3 wire.

Distribution transformer At distribution and transmission (consumer side). Δ-Y, 4wire.

MVA.

KVA.

 Voltage rating

Usually stepped down to 11kv.

Usually stepped down from 11kv to 415v.

• Cooling system

ONAF, OFAF, ONWF, OFWF

 Capacity

Usually ONAN.

Primary Distribution Transformer’s parts

Rod Gap Arrester

r

Transformer type Core type transformer

Winding

Core

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.

Transformer Core type

Comparison between core & shell type transformer Angular

Straight

Performance

 Reduce reluctance against the  Provides more reluctance magnetic flux by reducing the to magnetic flux due to gaps between sheets. Hence more number of gaps. So lessen the iron loss and performance is well below betters the performance. 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.

Products / Services: 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

Process flow diagram PPM

• Design product • Estimate cost

CPL

• Test raw materials • Report

Plant

• Electrical • Mechanical

• Test completed transformer Testing • Report

Name of Raw Materials CRGO Silicon Steel Sheet

Specification of materials Grade M-5 (width 0.3mm, density7.65kg/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

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

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

Transformer leg

Active Part

Tapping

Core

Insulation Board

Insulation Paper over winding

Testing

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.