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What would be the operating polarity of the conductor┬а in homoploar HVDC scheme
all conductors are operated with positive
all conductors are operated with negative
One with positive and rest conductors are operated with negative
One with negative and rest conductors are operated with positive
all conductors are operated with negative
In a homopolar HVDC transmission scheme, all conductors are operated at the same polarity, typically negative, with the return path provided by the ground or metallic return. Negative polarity is chosen to minimize radio interference and audible noise generated by corona discharges.
In a homopolar HVDC transmission scheme, all conductors are operated at the same polarity, typically negative, with the return path provided by the ground or metallic return. Negative polarity is chosen to minimize radio interference and audible noise generated by corona discharges.
VopтАЛ<0 тАФ Operating voltage is maintained at a negative potential relative to ground potential of 0V
IlossтАЛтИЭ(VconductorтАЛтИТVcoronaтАЛ) тАФ Corona loss dependent on potential difference
The scheme utilizes a single-polarity transmission system where the DC potential is kept negative relative to the earth. Because the corona inception voltage for negative polarity is higher than for positive polarity, operating the conductors at a negative potential significantly reduces the corona loss and electromagnetic disturbances caused by ionization of the air surrounding the conductor.
Homopolar schemes use ground or metallic return.
Negative polarity is standard to reduce corona effect.
Used mainly for low power capacity or early stages of HVDC development.
Increased risk of earth fault currents in ground-return systems.
Lower corona loss compared to positive polarity
Reduced radio and television interference
Simpler converter station design
Persistent ground currents can cause electrolytic corrosion
Interference with nearby underground metal structures
Higher insulation requirement due to earth resistance
Long-distance power transmission with limited capacity
Back-to-back HVDC conversion stations
Early stage HVDC pilot projects
The corona inception voltage for negative DC is higher, leading to lower corona losses than positive DC.
Option A is incorrect because positive polarity increases corona loss and audible noise.
B is correct тАФ Homopolar HVDC systems operate all conductors with negative polarity to minimize corona-related losses and environmental disturbances.
Always remember that in power transmission, 'negative polarity' is preferred for DC overhead lines to minimize atmospheric ionization effects near the conductor surface.