Dual-end Traveling Wave Fault Location Of Distribution Network Based On Zero-mode Line-mode Time Difference

With the rapid development of modern society,the reliability and intelligent management of power distribution network are increasingly required.With the expansion of urban scale,distribution network faults account for an increasing proportion of the whole power network faults.Therefore,accurate fault location of distribution lines is of great significance for the rapid restoration of power supply in distribution network.At present,the traveling wave method is widely used in fault location of transmission network,while the traveling wave method of distribution network is mainly based on the traveling wave location of transmission network-However,in view of the particularity of the distribution network,there are many problems in the application of the traveling wave location method and requirements in the distribution network.For example,the distance of distribution line is generally short,and the accuracy of ranging is higher.When the distribution line is single-phase grounded,the traditional double-terminal traveling wave fault location method can not meet the requirements of the accuracy of distribution network fault location.Therefore,based on the modulus analysis,this paper proposes an improved algorithm of double-ended traveling wave ranging based on zero-mode line-mode time difference,and the feasibility and accuracy of this method are verified by simulation.Firstly,this paper reviews the development process of traveling wave fault location technology,and briefly expounds the theoretical basis of wavelet analysis and modulus analysis in the application of grounding fault location in distribution network.Among them in the wavelet analysis,because there are infinite kinds of wavelet basis in theory,the transformation results of different wavelet basis cannot be compared one by one,this paper summarizes the method of optimizing the appropriate wavelet basis on the basis of analyzing the characteristics of traveling wave signal.In the modulus analysis,according to the characteristics of distribution network lines,the model characteristics of zero-mode lines are analyzed and the initial voltage traveling wave of the fault modulus at different distances is analyzed and simulated.On this basis,the merits and demerits of single-ended traveling wave ranging and double-ended traveling wave ranging are summarized,and several factors that affect the ranging accuracy are analyzed.To generally introduce the double-end traveling wave fault location mainly depends on both sides of communication pair,inconsistent when traveling wave fault location device clock on both ends fixed measuring time and other factors to form deviation,will cause bigger error,fault location precision of the quasi appear unable to test phenomenon,put forward a kind of based on time difference of zero line mould double-end traveling wave distance measuring algorithm,this algorithm fundamentally eliminate the pair are not synchronous ranging impact on both sides.Then,in order to explain the causes of the ranging error of the distribution network in more detail,this paper qualitatively verifies and explains several factors that affect the ranging accuracy by calculating and simulating the waveform.At the same time,considering the wide application of distribution network hybrid line,the engineering algorithm of traveling wave location of distribution hybrid line is discussedFinally,a distribution line example model is built,and the single-phase grounding fault simulation of 10kV distribution line is carried out by using ATP and Matlab simulation software.The precision values of clock asynchronization in different modes,different transition resistances,different fault positions and other related factors are obtained to form a table for comparative analysis.The simulation results show that the improved algorithm based on zero-mode line-mode time difference is not affected by transition resistance,clock unsynchronization and traveling-wave reflection,and it can solve the timing error problem of two-way traveling-wave fault location,which lays a foundation for the further development and application of traveling-wave fault location technology in distribution network.Figure[43]Table[24]...