Measurement Method of Capacitive Current in Distribution Network Under Parallel Operation of Double Arc-suppression Coils

With the expansion of the medium-voltage distribution network, the capacitive current continues to increase. To prevent arc overvoltage caused by excessive ground current, distribution networks commonly install arc suppression coils at the neutral point to counteract the capacitive current at the grounding point. As the network load grows, the capacity of a single arc suppression coil cannot meet the compensation requirements. Therefore, double arc-suppression coils are parallelly operated to increase compensation capacity. To address the challenge of measuring capacitive current in the case of parallel operation of double arc-suppression coils, this paper proposes a capacitance current measurement method based on multi-frequency injection signals.Through simulation experiments, the most critical parameters, particularly ground capacitance, can be measured with very high precision, with relative errors all below 0.3%. In laboratory tests of simulated distribution network systems, the majority of errors are within +/- 4%, highlighting the strong adaptability, simplicity in calculation, and high measurement accuracy of this method.