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At receiving end of secondary distribution substation voltage is
Stepped up to 220 kV
Stepped down to 66 kV
Stepped down to 11 kV
Stepped down to 440 V
Stepped down to 440 V
In an electrical power distribution system, the secondary distribution stage involves stepping down the voltage from the primary distribution level (typically 11 kV or 33 kV) to the consumer utilization voltage. In India, this receiving end secondary voltage for residential and commercial low-voltage consumers is standardized at 415 V/440 V (three-phase) or 230 V/240 V (single-phase).
In an electrical power distribution system, the secondary distribution stage involves stepping down the voltage from the primary distribution level (typically 11 kV or 33 kV) to the consumer utilization voltage. In India, this receiving end secondary voltage for residential and commercial low-voltage consumers is standardized at 415 V/440 V (three-phase) or 230 V/240 V (single-phase).
VlineтАЛ=3тАЛ├ЧVphaseтАЛ тАФ Relationship between line and phase voltage in star-connected distribution systems
VsecondaryтАЛ=VprimaryтАЛ├ЧN1тАЛN2тАЛтАЛ тАФ Transformer turns ratio governing the step-down process
The distribution transformer located at the load center steps down the primary voltage (e.g., 11 kV) to the secondary level using electromagnetic induction. The secondary side is connected in star configuration with a grounded neutral to provide both phase-to-neutral (230 V) and phase-to-phase (400 V - 440 V) voltages to accommodate diverse domestic and industrial loads.
Primary distribution usually operates at 11 kV, 22 kV, or 33 kV.
Secondary distribution steps down voltage to 415 V/440 V phase-to-phase.
The transformer used is typically a Delta-Star transformer with the neutral point solidly grounded.
The 440 V standard is common for heavy industrial/commercial supply, while 415 V is the standard distribution voltage.
Ensures safe voltage levels for household appliances
Allows for economical transmission over short distances within colonies
High current requirements lead to higher I2R losses compared to high voltage distribution
Requires larger cross-section conductors for the same power capacity
Domestic lighting and appliance power
Small-scale industrial motor loads
Commercial building electricity supply
The term '440 V' in the option refers to the 3-phase line voltage of the low-voltage distribution network.
Options A, B, and C refer to high voltage levels associated with Transmission (220 kV), Sub-transmission (66 kV), and Primary Distribution (11 kV) respectively.
D is correct тАФ The secondary distribution system steps down the voltage to 440 V (three-phase) or 230 V (single-phase) to be safe and usable for consumer-end loads.
Always remember the voltage hierarchy: Transmission (>132 kV) тЖТ Sub-transmission (66 kV/33 kV) тЖТ Primary Distribution (11 kV) тЖТ Secondary Distribution (440 V/230 V).