Study Of Single-ended Fault Location On Transmission Lines Based On Power Frequency Component

The electric transmission line is an important part of electric power, which is responsible for the transmission of electric energy. As the electric transmission lines are chronically exposed in the natural environment, they are more likely to have malfunction. Once the malfunction happened, the accurate orientation of the fault points becomes a problem that needed to be focused. It can not only save particular manpower and material resources, but also bring positive effect to the safety,stability and economy operation of the whole electrical power system by locationing of fault apace and accurately.This paper is based on power frequency component of the single-ended ranging principle to have a study of various types of short circuit fault occurred on transmission lines. In the meantime, have an analyzation of the stable time window after the failure and algorithm design of the time window of the automatic selection,in order to improve the ranging accuracy of the principle of power frequency range and provide reference for the rapid and exact selection of the microcomputer protection device’s time window, which adopts the ranging principle of power frequency component. In this paper, the research contents mainly include the following:1. Detailed analyses the basic principles of single-end fault location method based on power frequency component in the lumped parameter model and the distributed parameter model; aiming at all kinds of fault happening in line,summarizes the corresponding model of fault location under general expression, and analyses the reasons of influence ranging accuracy.2. Aiming at the fault after the stable’s time window’s selection problem, this paper proposes a stable time of the fault phase current differential window extra cation algorithm. The algorithm by using the fault phase current differential treatment,highlight the fault transition state. And by using the threshold value to eliminate he fault transition stage then determine the stability time window. At the same time make algorithm design of fault type judgement, power frequency component extraction and ranging principle in the process of fault location.3. Using the simulation software PSCAD structures, geometric parameter model and distributed parameter model to make emulation of the single-phase grounding short circuit and two phase short circuit fault. Combined with the simulation waveform, with the aid of MATLAB software to validate the proposed time windowselection algorithm automatically. Using the single side ranging principle based on the lumped parameter model and distributed parameter model to locate the fault point.Then analyse the ranging results, compare the precision of the different two kinds of distance measuring principle.The automatic extraction algorithm of the stable time window after failure raised in this papers can locate the fault steady state fast, and using the time window can get the frequency components of voltage and current after failure accurately.