Measurement Technology of Grounding Capacitance of Distribution Network Based on the Graded Adjustment of Grounding Transformer Winding

Abstract

The traditional method of measuring grounding capacitance of distribution network is greatly affected by neutral grounding method, and the influence of harmonic elimination resistance and internal impedance of voltage transformer on measurement accuracy cannot be eliminated. Therefore, this paper proposes an accurate way to measure grounding capacitance of the distribution network which is not affected by the neutral point grounding method. It uses a special Y/ Δ-connected grounding transformer with taps connected to the distribution network to change the zero-sequence voltage of the distribution network by adjusting the grounding tap of the high-voltage side winding of the grounding transformer, and obtains the required zero-sequence through measurement voltage and zero sequence current to find the capacitance to ground of the system. The proposed measurement method is analyzed in PSCAD/EMTDC, which shows that the method has high measurement accuracy and is safe, simple and economical for the measurement of ground capacitance current.