An On-Line Measurement Method of Capacitance Current in Resonant Earthed Distribution Network Based on Injected Signal

This paper proposes a method of online measurement of capacitive current in resonant-earthed distribution networks based on injected signals to address the issues caused by inaccurate arc suppression coil parameters and internal impedance of voltage transformers on measurement results. In this method, AC current signal is injected into the secondary side of the voltage transformer at the neutral point, the feedback voltage is obtained through the auxiliary secondary winding of the voltage transformer at the bus bar, and the equivalent circuit of the injected signal is established. By withdrawing the arc suppression coil during the measurement process, the complexity of the measurement process can be reduced, and the errors introduced by inaccurate actual parameters can be eliminated. By utilizing the auxiliary secondary winding of the bus voltage transformer, the voltage drop caused by the injected signal in the grounded branch can be directly obtained, avoiding the influence of the impedance of the voltage transformer itself on measurement accuracy. Finally, the effectiveness and applicability of the proposed method were verified using Matlab/Simulink.