(super) Uhv Transmission Line Fault Location Method

With the UHV DC transmission project of the YunGuang'±800kV being const- ructed, UHV transmission project has been carried out in China.UHV transmission line of Electric power system fall fault easily because of the long span distance,the large power capacity,the wide distribution,the complexity of geology or environment,the changeful meteorology and many other causes.the exact fault location will reduce the manual work and find out unclear faults.Resuming transport in time and credible power supplying would be available to stabilization and economical operation of power system.therefore the research on new principle of fault location for UHV transmission line is of great practical significance.The main contents of this thesis are:(1)The main factors of affecting the precision of UHV line fault locatin is presented,the tradition fourier method,the inaccurate transmission line parameters and length can cause large fault location error;the improved fourier,method of changing datasection is presented,and a method,which is based on the prefault signal,to calculate the real parameter and the length and of the single-circuit line and the double-circuit line on line is also presented.the presented method can calculate the positive,negitive parameter of single-circuit and double-circuit line exactly,the datas are the base of the following fault location mothod.(2)The parallel transmission lines is on the same tower,the mutual inductance is exist on the phase-phase,but also on the line-line.The paper gets the differential network and the same network from the coupling double-circuit transmission lines firstly,and then according to the voltage and impedance of the differential network is zero,the paper present an time-domaim algorithm which suited for the UHV parallel transmission lines,the algorithm calculated voltage and current distribution at the fault point derived at one terminal,and then obtained the fault distance by the ideal long ACare volt-ampere characteristic,and check up the present algorithm by a system of 750kV parallel transmission lines finally. (3)At present,the report on the characteristic of the DC arc is rare from home and abroad,the paper construct the DC arc model of the UHV which according to the research on the DC arc stove firstly,and then present an algorithm suited for the UHV DC transmission lines,the algorithm calculated voltage and current distribution at the fault point based on Bergeron model,and then obtained the fault distance by the ideal long DC arc volt-ampere characteristic,and check up the present algorithm by±800kV yunguang DC transmission lines finally.(4)With the rapid development of the micro-electronics and further understanding of the rule of the travelling wave,the device had applied on the EHV and UHV widely,but the travelling wave method had some limitation。The paper present two fault location algorithms to eliminate the limitation of thetravelling wave method,the algorithmⅠobtained the fault distance according to the time- margin between the reclosure pulse and the reflected pulse from fault point by cubic B-spline wavelet,the algorithmⅡobtained the fault distance through the critical current of fault phase,and check up the present algorithm by UHV transmission lines finally.