Research On Fault Location Method Of High Voltage Transmission Line With Series Compensation Equipment

In recent years,as more and more UHV,EHV transmission lines are built and this section is put into operation,in order to improve the stability of the power system and use the existing transmission corridor to further enhance the transmission capacity of the line,the series compensator has been used continuously.The operation of the series compensator has many adverse effects on the application of the conventional fault location method for transmission lines.Therefore,it is of great significance to study the fault location method of UHV and EHV transmission lines with series compensators,which can quickly and accurately locate the fault,eliminate the fault,restore power supply and improve the reliability of the power system.The main work and research results of this paper are as follows:First,the influence of series compensation capacitor,protective device,metal oxide limiting device(MOV)and installation position of series compensator on fault location method of conventional transmission line are studied and analyzed.Through the study and analysis of the time of MOV conduction and the working state of the series compensator,two methods of solving the voltage of the series compensators are given: the series compensated voltage solution method based on the integral equation and the series compensated voltage solution method based on the symmetric component method,and the two methods are not affected by the nonlinear element in the series compensator.Secondly,on the basis of the analysis of conventional transmission line double terminal fault location methods,three kinds of fault location methods,which are suitable for transmission line with series compensation equipment,are obtained by combining the analysis results of the influence of each component of the series compensator to the fault location.They are two terminal synchronous fault location method based on the differential equation(method one),double terminal asynchronous fault location method based on complex equation(method two)and double terminal synchronous fault location method based on complex equation(method three).The applicability of the three methods is theoretically analyzed.The results show that the three methods are not affected by the fault types of line grounding and short circuit,the grounding transition resistance and the location of the fault point,thus the applicability of these methods is explained theoretically.Finally,the MATLAB simulation software is used to build the transmission line model containing the series complement device.From the accuracy of fault location,the robustness of the method,the resistance of the fault point and the sensitivity of the distance of the fault point,the three methods are compared and compared.The simulation results show that the method three is the best and the method two is worse than three,and the method one is relatively poor.These three methods can meet the requirements of the fault location error less than 1%,thus providing a reference for the selection of the suitable fault location method.In addition,a large number of digital simulations of MOV's single exponential model are carried out,and its influence on fault location is further analyzed.