Fault Location Of Single-phase Earth For Distribution Network Based On Transient Information

With the development of society and increasing electricity consumption, thereliability of distribution network is more and more concerned by electricity sector andelectricity users. According to the relevant data show that distribution network fault inthe70%above is the single phase grounding fault, and most of them transient faultlocation. Current distribution is for small current neutral grounding system, the steadycurrent weak feature is not obvious after single phase to ground fault occurred, thetraditional fault location methods based on steady-state information are limited.However,the transient information is full and it reflects the failure of the process andcharacteristics completely,using this information, it can not only locate permanent faultpoints, but also locate the transient faults. Therefore, researching on fault location ofdistribution network based on transient information, is of great theoretical significanceand practical value.This paper analyzes the transient characteristics of the distribution network afterthe single-phase ground, using Laplace transform, the paper deduce the line distributedparameter image function model in the zero state network. And it analysis the systemshort circuit transient process and its calculation method based on this image functionmodel and image function symmetrical components transform. At the same time, it alsointroduced the frequency characteristics of zero-sequence parameters, and laid thetheoretical foundations for later fault location.In this paper, using of zero-sequence network, with the line distributed parameterimage function model,it presents a two-terminal fault location methods based onStehfest algorithm. Without considering the frequency characteristics of thezero-sequence parameters and considering the frequency characteristics of the two cases,it derivate the image function distance equations. By Stehfest algorithm on rangingequation for numerical inversion, it obtain the minimum of the distance equation in theregion and the numerical matrix, to the square sum of the matrix elements and aminimum target to determine the fault distance. This paper built a simulation model inEMTP and calculated by MATLAB, to verify the correctness of the method. With thistwo-terminal location algorithm, using the fault location XSJ-1610prototype, this paperpromoted the dynamic simulation experiments to further validate the usefulness of thismethod. Meanwhile, this paper presents a single-terminal fault location method based oneigenvalue which according to the relation with the decay time constant、frequency andfault distance of transient components in zero-sequence voltage (or zero-sequencecurrent). The method by measuring the zero-sequence voltage and fault port port as afunction of the relationship, obtained as a function of the single-ended location equation,by the characteristic of special frequency bands (SFB), it presents the equivalent formof this equation. Revising the decay time constant of the eigenvalue in the SFB, into theequation, it obtain the minimum amplitude of the equation in the region and theamplitude matrix, to the sum of the matrix elements and a minimum target to determinethe fault distance. Similarly, simulation and dynamic simulation experiments to verifythe correctness and practicability of this single-ended fault location.