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Chapter 1 of 12 тАв Page 1 of 248ЁЯФТ Protected PDF тАв Watermarked
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Arcing on transmission line is prevented by connecting
Inductor in neutral
Resistor in neutral
Capacitor in neutral
None of above
Inductor in neutral
Arcing on a transmission line, particularly during a line-to-ground fault, is prevented by using an Arc Suppression Coil, commonly known as a Petersen Coil. This inductor is connected between the neutral point of the system and the ground to neutralize the capacitive charging current of the line.
Arcing on a transmission line, particularly during a line-to-ground fault, is prevented by using an Arc Suppression Coil, commonly known as a Petersen Coil. This inductor is connected between the neutral point of the system and the ground to neutralize the capacitive charging current of the line.
ICтАЛ=3тЛЕ╧ЙтЛЕCgтАЛтЛЕVphтАЛ тАФ Capacitive fault current
L=3тЛЕ╧Й2тЛЕCgтАЛ1тАЛ тАФ Inductance required for tuning
When a line-to-ground fault occurs in an unearthed system, the line-to-ground capacitance (CgтАЛ) causes a significant leading fault current, which sustains the arc at the fault location. By installing a Petersen Coil with inductance (L), an inductive current (ILтАЛ) is produced that is equal and opposite to the capacitive fault current (ICтАЛ). This effectively cancels the reactive fault current at the point of the fault, allowing the arc to extinguish naturally without interrupting the power supply.
Petersen coil grounding is primarily used in medium voltage networks to prevent sustained arcing.
The system is said to be 'tuned' when ILтАЛ=ICтАЛ.
It eliminates the need for circuit breakers to trip immediately upon transient single line-to-ground faults.
The neutral is not directly grounded but grounded through a variable reactor.
Reduces fault current magnitude significantly.
Allows arc extinction without tripping the circuit breaker.
Improves supply reliability for transient faults.
Increased risk of insulation failure due to temporary overvoltages.
Requires periodic tuning of the inductor if system capacitance changes.
Medium voltage overhead transmission lines.
Rural distribution networks where transient faults are frequent.
The condition where ILтАЛ=ICтАЛ is called resonant grounding.
Resistor in neutral (Option B) is used for High Resistance Grounding (HRG) to limit fault current, but not specifically to cancel capacitive charging current for arc suppression.
A is correct тАФ An inductor, known as a Petersen coil, is connected between the neutral and ground to neutralize the capacitive fault current and prevent arcing.
Always remember that the Petersen coil is designed specifically to resonate with the system capacitance (CgтАЛ), making it a classic application of R-L-C resonance in power systems.