Research On Fault Location Of Transmission Network Based On Improved Impedance Method

The trend of energy transition is unstoppable,and electric energy occupies a leading position in the process of energy transition.The improvement of the fault location accuracy of transmission lines will inevitably speed up the development of electric energy.More precise fault location has become the goal of many researchers,and derived many research directions.The field of fault location includes cutting-edge technologies such as big data and artificial intelligence.This thesis combines the standard transmission network to test the fault location of the transmission line.First,it introduces the research background of fault location,summarizes the current research status of fault location methods,lists some available fault location algorithms,analyzes the shortcomings of traditional methods,and briefly outlines the main points of different types fault location algorithms of transmission lines.At the same time,this chapter summarizes the research content of this thesis.Regarding the problem of conventional transmission line fault location,a series of improvements are made on the basis of the traditional double-terminal fault location algorithm.The third-order Taylor series was used to decouple the line model,the traditional fault location equation was transformed into a complex equation,and the nature of the complex number was used to avoid the pseudo-root of the equation,and the algorithm is improved for the cross-country fault.The location equation is improved by by dividing transmission line area and approximate strategy,so that the location algorithm can locate the cross-country.Since there are series compensation devices in the transmission network,when a fault occurs,the impedance of these devices is highly non-linear.The six-sequence component method is introduced to decouple the line model,and for the faults on the left and right sides of the series compensation device,their respective fault location algorithms are discussed.The fault location algorithm deduced in this chapter does not need to determine the fault area,which simplifies the location process.At the same time,the new algorithm needs to reselect the phase sequence to avoid the nonlinear impedance of the series compensation device.The improved fault location algorithms proposed in this thesis are only applicable to a single line.In order to apply the algorithm to a large-scale transmission network,the transmission network needs to be divided into simpler line,the IEEE Bus14 transmission network is divided into different types of transmission lines to lay a good foundation for the subsequent fault location simulation test.The criteria for the fault branch and the fault phase of the hybrid transmission network are derived and carried out on the double hybrid transmission line.The criterion derivation,similarly,the criterion of the fault branch and fault phase of the multi-terminal transmission line is derived on the 3-terminal transmission line.In order to verify the feasibility and accuracy of the fault location algorithm,simulation tests were carried out on the IEEE Bus14 transmission network,a large number of fault location tests were carried out using the new algorithm,including evolving fault and cross-country fault.At the same time,this chapter also tested other influencing factors of the new algorithm.Not only that,a large number of simulation experiments have also been carried out on the series compensation line,proved that the algorithm can accurately locate various types of faults.Other influencing factors of the algorithm on the series compensation line have also been tested,which proves that the performance of the algorithm is excellent.