Resonant grounding;  Grounding capacitor current;  Automatic tracking;  Improved E0 method

With the continuous increase of the capacitor current of the system, more and more power grids adopt resonant grounding mode. The resonant grounding method effectively suppresses the re-ignition of single-phase ground fault arc and the occurrence of arc overvoltage, which greatly improves the operation reliability of medium-voltage power grid. An important technical difficulty in the promotion of resonant grounding method is the automatic tracking and measurement of system capacitance current. In order to solve this problem, based on the analysis and comparison of several existing automatic tracking measurement methods, an improved E0 method is proposed.10 kV high-voltage physical simulation experiments show that this method can effectively identify whether the system is in an overcompensated state or undercompensation state, and can correct the value of E0 method online in real time.