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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