Research Of Distribution Network Fault Location Technique Based On Traveling Wave Mode-component Time Difference

The power system fault will affect the safety operation of the system, which brings inconvenience and economic loss to the power customer,or even has a damaging impact upon the national production when it becomes serious. Quickly location of the fault point, removal of the fault line and recovery of the power supply are the requirements for the development of smart grid. Fault location technology based on traveling wave has a good performance in the field of line fault location, which is a hot topic of research.This paper first analyzes the characteristics of aerial-modal traveling wave and zero-modal traveling wave; studies on the effects about aerial-mode component and zero-mode component of traveling wave head with considering the ground, frequency and propagation distance of the line distribution model; introduces some existing algorithms about the analysis of fault traveling wave head, compares their advantages and disadvantages.Second, in view of the shortcomings of existing algorithms, a transient traveling analysis method based on intrinsic time-scale decomposition(ITD) is proposed to improve the traveling wave feature extraction efficiency in power system. This method analyze fault traveling wave signal, decomposes a signal into several intrinsic rotation components and a trend component,and extract the high frequency component for fault analysis. Lastly, based on the analysis of transmission characteristics of zero-mode component and aerial-mode component of traveling wave in distribution network, a new fault location method for distribution network is presented.According to the historical fault data of distribution network lines, the relationship between zero-aerial mode component time difference and fault distance,and the relationship between zero-aerial mode component time difference and zero mode velocity are fitted. According to the fitting curve, fault-section location is identified based on transmission time difference of zero-aerial mode component, and a accurate fault location method based on double-ended zero mode components is studied.The simulation results show that the wave head analysis method based on ITD can effectively reduce the recording time error of fault traveling wave signal to reach theacquisition point, and has higher precision and efficiency for power grid fault location. The proposed method can accurately judge the fault section and find the fault location in various grounding fault conditions.