A novel method of measuring capacitance current for ineffectively earthed power systems

Capacitance current is an important parameter for single phase grounding faults protection and control in ineffectively earthed power systems. A novel method for the capacitance current measuring is presented in the paper. With injecting a tested signal into the open-delta secondary of the voltage transformer, the voltage of the open-delta secondary and the voltage of the star secondary are measured. And the capacitance current to earth can be calculated directly for the ineffectively grounded systems. The novel method is tested in a dynamic power system. Test results show that the method is simple, convenient, and precise in measuring the capacitance current in real-time without power supply interrupting, and can reduce the influence of voltage transformer leakage impedance.