Research on improved signal injection method for capacitance current measurement in distribution networks
The signal injection method is a common approach for measuring the ground capacitance current in distribu-tion networks.The choice of the injected signal's frequency directly affects the measurement accuracy.This paper presents an improved signal injection method for measuring capacitive current in distribution networks.Firstly,the leakage inductance value of the voltage transformer is determined by injecting a high-frequency signal.Then,the resonant frequency of the ground capacitance in the distribution network is identified through a frequency sweeping method,enab-ling the calculation of the ground capacitance.Finally,the current value of the ground capacitance is obtained by divi-ding the rated voltage of the network by the ground capacitive reactance.By leveraging the reduction effect of series capacitance on the total system capacitance,this study effectively enhances the precision of capacitance current mea-surement.Both simulation and laboratory experiments validate the feasibility and efficacy of the proposed capacitance current measurement method.
distribution networksignal injection methodcapacitance current measurementground capacitance reso-nant frequency
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