Research On Diagnosis Method Of Grounding Fault Of Transmission Lines

Transmission lines carry vital responsibilities in the transmission process and are important components for connecting power stations and users.Once the line fails,social production and life will be seriously affected.Due to the extremely special environment of the transmission line,it is very prone to failure,especially the probability of ground fault.Moreover,the method of manual inspection is no longer suitable for the current power system to query the fault type.Therefore,it is very necessary to explore the diagnosis method of the grounding fault of the transmission line to achieve the purpose of quickly diagnose the type of ground fault.Fault information is often included in the signal that the line has failed.When a single-phase or two-phase ground fault occurs on the transmission line,one or two phases of the fault will contain a fault signal.Moreover,the external signal is very easy to cause interference to it,which causes the fault signal feature to be missing,and it is difficult to completely extract the fault feature.Therefore,the complexity of comprehensively analyzing the ground fault and the difficulty of extracting the fault feature are greatly increased,and the fault phase and the non-fault phase when the ground fault occurs on the line cannot be accurately diagnosed.A problem in which the signal characteristics are missing during the ground fault of the transmission line for the fault signal.In this paper,the combination of variational mode decomposition(VMD)and dynamic time warping(DTW)and the method of mutual approximation entropy(CApEn)are applied to the ground fault diagnosis of transmission lines for the first time.The VMD-DTW and CApEn used are explored.Whether the two methods can effectively diagnose the ground fault of the transmission line.First,when a single-phase grounding or two-phase grounding fault occurs in the transmission line,the current signal easily acquired at the nodes at both ends of the faulty line is used as the fault signal.Then,each phase current signal is analyzed by the VMD-DTW analysis method and the CApEn analysis method.Finally,the phase of the transmission line fault is diagnosed based on the DTW distance and CApEn entropy of each phase.In order to fully explain the reliability of the adopted method and avoid the influence of accidental factors,the IEEE 14-node standard test system and the IEEE9-node standard test system are selected,and two different test systems are analyzed and verified.And compared with VMD-PE analysis method and EEMD-CApEn analysis method.Simulation experiments show that the analysis method and analysis method used in the article can accurately and effectively diagnose the fault phase of the transmission line.Figure [42] table [13] reference [68].