A Capacitance Current Measurement Method for Resonant Grounding Distribution Network Considering Damping Resistance

摘要

Aiming at the measurement error of capacitance current for resonance grounding distribution network caused by damping resistance and the internal impedance of voltage transformer, a capacitance current measurement method for resonant grounding distribution network considering damping resistance was presented in this paper. The method is to inject a non-power-frequency signal into the distribution network through one of the two transformers of the voltage transformer inside the arc-suppression coil or zero-sequence voltage transformer of distribution network, and the returned signal is measured from another no-load voltage transformer, which eliminates the influence of the voltage transformer's internal impedance. By establishing the zero-sequence equivalent circuit of distribution network, the capacitance current can be obtained accurately which eliminates the influence of damping resistance. Finally, a 10kV distribution network simulation model was established by PSCAD simulation software, the simulation analysis results showed the proposed method can accurately obtain the capacitance current of distribution network.