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Three phase transformer can be used in
A) Sub station
B) Industries
C) Generating station
D) All of the above
All of the above
A three-phase transformer is a static electromagnetic device used to step up or step down alternating voltage levels in a three-phase power system. It plays a critical role across the entire electrical power system, including generation, transmission, distribution, and industrial applications. Because electrical energy is universally generated, transmitted, and heavily consumed as three-phase power, three-phase transformers are ubiquitous.
A three-phase transformer is a static electromagnetic device used to step up or step down alternating voltage levels in a three-phase power system. It plays a critical role across the entire electrical power system, including generation, transmission, distribution, and industrial applications. Because electrical energy is universally generated, transmitted, and heavily consumed as three-phase power, three-phase transformers are ubiquitous.
SN=3⋅VL⋅IL — Total apparent power in a balanced 3-phase system
VL2VL1=k⋅N2N1 — Line voltage transformation ratio (where k depends on configuration like Δ−Y or Y−Δ)
It operates on Faraday's law of electromagnetic induction and mutual induction between three sets of primary and secondary windings linked by a common magnetic core. Alternating voltage applied to the primary windings creates a time-varying magnetic flux in the core, which induces a phase-displaced alternating electromotive force (EMF) in the corresponding secondary windings.
Three-phase transformers are used at generating stations as Generator Step-Up (GSU) transformers to raise voltage for long-distance transmission.
They are used in transmission and distribution substations to step down high voltages to primary and secondary distribution levels.
Industries utilize three-phase transformers to step down voltage to standard operational levels (e.g., 415 V) for driving heavy 3-phase induction motors and loads.
Requires less conductor material and core iron compared to three single-phase transformer units of equivalent capacity.
Occupies significantly less floor space and has lower overall weight and lower cost.
If one phase suffers a major fault, the entire three-phase unit usually must be taken out of service for repair.
Transportation of a single large bank can be more challenging than transporting smaller single-phase units.
Thermal, hydro, and nuclear power plant step-up switchyards.
Primary and secondary electrical transmission and distribution substations.
Industrial plants, factories, and commercial buildings driving three-phase machinery.
Option A (Sub station): Correct, as distribution and transmission substations rely on 3-phase transformers.
Option B (Industries): Correct, industrial machinery requires 3-phase power, stepping down 11 kV / 33 kV to 415 V.
Option C (Generating station): Correct, step-up transformers raise alternator voltage (e.g., 11 kV to 220 kV or 400 kV).
Option D (All of the above): Since all three applications utilize three-phase transformers, Option D is the correct comprehensive answer.
D is correct — Three-phase transformers are essential equipment used universally in generating stations, substations, and industrial facilities.
Remember that a single 3-phase transformer has ~15% higher efficiency and occupies less space than a bank of three 1-phase transformers of equivalent overall kVA rating.