ppt on transformer

7/23/2019 Ppt on Transformer

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Transformer

Distribution

Core type

Straight cut Angular cut

Shell type

Power

ONAN(Oil natural Air natural)

Categorizingthe transformerproduction at GEMCO


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Comparison between power & distribution transformer

PowerTransformer

DistributionTransformer


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Power transformer Distribution

transformer

Installation

Connection

Capacity

Voltage rating

Cooling system

At substation

(generation side).

- or Y- , 3 wire.

MVA.

Usually steppeddown to 11kv.

ONAF, OFAF,

ONWF, OFWF

At distribution and

transmission

(consumer side).

-Y, 4wire.

KVA.

Usually steppeddown from 11kv to

415v.

Usually ONAN.

Comparison between power & distribution transformer


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Primary Distribution Transformers parts

rRod Gap Arrester


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Core type transformer

Transformer type

Winding

Core


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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 transformersbecause of a reduced height and better mechanical protection tothe winding because it is surrounded by core.

From a manufacturing standpoint, core-type & shell-typedesigns are very similar.


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Transformer Core type


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Angular StraightPerformance Reduce reluctance against the

magnetic flux by reducing thegaps between sheets. Hence

lessen the iron loss and

betters the performance.

Provides more reluctance

to magnetic flux due tomore 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 makeit angular.

Cost is well below the

angular cut.

Preference Preferred where efficiency isvital.

Mostly used due to the

less cost.

Comparison between core & shell type transformer


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I ) Transformers:

Power Transformer, 3 Phase, 33/11KV, 1 MVA to 5 MVADistribution 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 KVADistribution Transformer, 1 Phase, 11/0.24 KV, 15 KVA to 25 KVA

Apart from these, other rated transformer could manufactured asper requirements of clients up to 5MVA

II)Repair & Miscellaneous Works:Damaged Distribution & Power Transformers up to 20 MVA

Products / Services:


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Process flow diagram

PPM

Design product

Estimate cost

CPL

Test raw materials

Report

Plant

Electrical

Mechanical

Testing

Test completed transformer

Report


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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%

purityMild 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


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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 Bm1.7Wb/m

IEC Standard:

76

Vector group:

DYN-11

Design specification


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The design is usually 6 step core section with Cylindrical coils

In design calculation

Design specification


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Summarizing the design:

Specification of the transformer to be designed

Chose Ez, Bm,

Calculate Area and Diameter for coreFind 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

Desi nin the tank

T f l


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Transformer leg

A i P


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Active Part

Tapping

Core

InsulationBoard

InsulationPaper overwinding

T i


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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


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ppt on transformer

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