1.Electric Power Research Institute of Guangxi Power Grid Co,Ltd;2.Electric Power Research Institute,CSG
The traditional method of measuring the ground capacitance of the distribution network is greatly affected by the neutral grounding method, and cannot eliminate the influence of the harmonic elimination resistance and the internal impedance of the voltage transformer on the measurement accuracy. For this reason, This paper proposes an accurate measurement method for the capacitance to ground of the distribution network that is not affected by the neutral point grounding method. Using a special Y/△-connected grounding transformer changes the zero-sequence voltage of the distribution network by adjust the grounding tap gear of the high-voltage side winding of the grounding transformer to the low gear to ensure that the zero sequence voltage of distribution network changes within the specified offset value, and the capacitance current to ground of the system can be obtained by measuring the required zero-sequence voltage and zero-sequence current. In the PSCAD/EMTDC simulation environment, the proposed method of measuring the ground capacitance is simulated and analyzed. The analysis results show that the method has high measurement accuracy and the process of measuring the ground capacitance is safe, simple and economical.