Identification of Neutral Grounding Fault in CT Secondary Circuit Based on Harmonic Characteristics of Grounding Current
It is difficult to identify the ground fault on the neutral line due to the small amplitude of the ground cur-rent at the CT neutral point,and it is easy to induce protection misoperation when an out-of-area fault occurs.A fault cri-terion for neutral line grounding is proposed based on the relative magnitude of odd and even harmonics of CT neutral ground current.Under the conditions of low current and high noise,the VMD-Prony algorithm is used to filter out the high-frequency noise signal of the neutral grounding current through VIMF mode decomposition and entropy sorting.The low mode component is smoothed by Savitzky-Gloay,and the VIMF component is reconstructed to obtain the noise reduc-tion signal.Finally,the Prony algorithm is used to obtain the harmonic component for neutral grounding fault diagnosis.Finally,the feasibility of the discrimination method is verified through on-site testing data and simulation data.
CT secondary circuitgrounding current harmonicsVMD-Prony algorithmfault criteria
万方数据
维普
