Study Of Fault Location For The High Voltage Transmission Line

In this thesis, the fault location algorithms of HV transmission line are evaluated at first, then the factors that affect the accuracy of the fault location are analyzed, and the proper solutions are presented. The majority of work that is presented in this thesis is listed as follow: The most problem of two-terminal fault location method is that the sampling of two-terminal dates is unsynchronized. Thus this thesis presents a new unsynchronized technique for two-terminal fault location. In this technique, the two-terminal date sampling unsynchronized angleδ is considered as a unknown quantity, and the fault location equation x=f(δ) is established. Superimposed components of two terminal electrical quantities are used in the algorithm. The unsynchronized angleδ is solved iteratively by equation Im(x)=0, and the accurate solution of x is found finally. Lots of simulation results show that the technique presented in this thesis can precisely locate the fault site and avoid the false solution. Because conventional single-terminal method of fault location can't eliminate the influence of fault resistance and the remote in-feed, its utility is limited. This thesis presents a single-terminal fault location technique that is used together with recloser. The technique takes advantage of reclosing of single-terminal recloser to eliminate the influence of the remote source impedance. A distributed parameter line model is used for the proposed algorithm, thus the technique can be used in HV transmission line.This thesis analyzes the influence of line length and parameters changing on fault location results. Lots of simulation results show the error of line length and parameters can cause the great locating error. Thus this thesis presents a method to estimate length and positive parameters of transmission line, and a method to estimate length, positive parameters and zero parameters of line at one time. Simulation results show that length and parameters of transmission line can be precisely revised by these methods, and the influence of line parameters and length varying on location precision is greatly cut down.