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The voltage rating of the transformer in a pole mounted substation is
11 kV / 400 V
11 kV / 230 V
33 kV / 400 V
None of above
11 kV / 400 V
A pole-mounted transformer is a distribution transformer mounted on an electric utility pole, specifically designed to step down the primary distribution voltage to a utilization voltage suitable for domestic and commercial consumers. In the Indian power distribution context, the standard primary voltage for these transformers is 11 kV, which is stepped down to a three-phase secondary voltage of 415 V (commonly referred to as 400 V).
A pole-mounted transformer is a distribution transformer mounted on an electric utility pole, specifically designed to step down the primary distribution voltage to a utilization voltage suitable for domestic and commercial consumers. In the Indian power distribution context, the standard primary voltage for these transformers is 11 kV, which is stepped down to a three-phase secondary voltage of 415 V (commonly referred to as 400 V).
VratioтАЛ=V2тАЛV1тАЛтАЛ=N2тАЛN1тАЛтАЛ тАФ Basic voltage transformation ratio
P=3тАЛVLтАЛILтАЛcos╧Х тАФ Power relation for three-phase distribution
The transformer operates on the principle of Faraday's Law of Electromagnetic Induction. The primary winding, connected to the 11 kV line, carries a high-voltage, low-current input. Through electromagnetic induction, this flux links to the secondary winding, which has fewer turns to produce the required low-voltage, high-current output of 415 V / 240 V line-to-neutral, suitable for consumer loads.
Pole-mounted transformers are typically used for local distribution in rural or urban residential areas.
The secondary output is a 3-phase, 4-wire system providing 415 V between lines and 240 V between line and neutral.
Transformer capacity for pole mounting is generally restricted to 250 kVA due to the structural limit of poles.
Low installation cost compared to pad-mounted substations.
Efficient space utilization in densely populated areas.
Limited power capacity due to physical weight constraints.
Exposed to environmental factors like lightning and severe weather.
Rural electrification networks.
Distribution networks for residential colony power supply.
Standard Indian distribution practice utilizes 11 kV / 415 V transformers.
Option B (230 V) is a phase-to-neutral voltage, not the full secondary line voltage rating.
33 kV / 400 V (Option C) transformers are typically used in indoor or outdoor plinth-mounted substations, not on poles.
A is correct тАФ The standard voltage rating for a pole-mounted distribution transformer in India is 11 kV / 400 V.
Remember that the secondary voltage 415 V is the line-to-line voltage; 240 V is the phase-to-neutral voltage. Often, textbooks use 400 V as a nominal value in calculations.