design and standardization of power transformer

8/9/2019 Design and Standardization of Power Transformer

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DESIGN AND STANDARDIZATION

OF POWER TRANSFORMER


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INTRODUCTION

Transformers are static devices, that transferselectrical energy from one circuit to another

circuit with same frequency.

A power transformer could be a bank of threesingle phase transformers connected in either

step-up(delta to star )and step-down(star to

delta).

Transformers are able to transfer 99.75% oftheir input power to output power.


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INDUCTION LAW

Vs = Ns d/dt WORKING PRINCIPLE

structural schematic diagram of Transformer

EMF EQUATION

E=4.44fN=4.44fNBA

TRANSFORMER RATING IN kVA?


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EFFECT OF FREQUENCY

y The time derivative term in Faradays law shows that theflux in the core is the integral of the applied voltage.

ENERGY LOSSESy Larger transformers are generally more efficient,

and those rated for electricity distribution usuallyperform better than 98%. Experimentaltransformers using superconducting windings

achieving efficiencies of 99.85%.


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POWER TRANSFORMER

POWER TRANSFORMER

SINGLE PHASE Vs THREE PHASE

TRANSFORMERS ADV AND DIS ADVANTAGES OF THREE PHASE

TRANSFORMERS


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POWER TRANSFORMERS

y Presently, most of the electric power for industrial andutility purposes, is generated by large hydro-electric plantsand steam power station in the form of three phase A.c. at afrequency of 50Hz.

y Step-up transformers transformers which raise the voltage, and

y Step-down transformers transformers which lower the voltage.

POWER TRANSFORMER


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TRANSFORMER CONSTRUCTION

yThere are general types of constructions

employed to achieve this in transformers.

y Core

yWindings

y Cooling ducts

y Transformer oil

y

Cooling of transformer


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Conservator and breather

Temperature indicator

Buccholz relay Bushings

Explosion vent


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Core &Windings of transformer

Paper covered insulated

copper strips or

continuously transposedcables are used for making

winding.


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Breather


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Transformer oil

Some of the important characteristics necessary or desirable

in transformer oil are described below.

Electric Strength

Resistance to emulsionViscosity

Purity

Flash point

Sludge formation


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Transformer tank


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Transformer losses

Iron or core losses

Hysteresis losses

Eddy current losses Copper losses


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Earthing arrangements

Earthing arrangementsCore earthing

Tank to tank cover earthing

Neutral grounding


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PETE- PAN ELECTRO

TECHNIQUES ENTERPRISES: TRANSFORMERS: TO IS : 2026-1977

Rating = 950 kVA

Rated voltage H.V = 11000 V

L.V = 416 V

Rated current H.V = 49.86 A

L.V = 1318.5 A Phases = 3

Frequency = 50 Hz

Conn. Symbol = Dyn 11

Year of manufacturing = 2003

Type of cooling : ONAN

Oil temperature rise : 450

Winding temperature rise : 550

Impedance volts : 5.04 %

Volume of oil : 660 (liters)

Mass of oil : 560 kg

Un tanking mass : 1675 kg

Total mass : 3250


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y HACK BRIDGE HEWITTIC AND EASON LIMITED:

y Oil in liters : 1330

y Year of manufacturing : 1965

y

Total mass : B.S.S.171:1959y RATING: 750 kVA

y Volts on load H.V : 11000 V

y L.V : 1486 V

y Amperes H.V : 39.4 A

y L.V : 1040

y Phases H.V : 3

y

L.V : 3y Temperature rise : 40/50 o C

y Frequency = 50 Hz

y Conn. Symbol = Dyne 11

y Year of manufacturing = 2003

y Type of cooling : ON

y % of Impedance : 5.19

y

Vector group : DY 11y Core of windings : 2010 kgs

y Weight of oil : 1145 kgs

y Total weight : 4970 3250


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THANQ

design and standardization of power transformer

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