Research On Fault Location Technology For Distribution Network

Precise distribution network fault location technology has an important practical significance for speeding up power supply processing and recovery speed, and reducing power losses caused by failure.Because of the complexity of distribution feeders and limitations of monitoring points, the current distribution network fault location can only be implemented in section targeting, which means it can only determine the fault point between two section switches instead of determining the accurate fault location.This paper proposes a technical approach to achieve accurate distribution lines fault location. This method combines the current distribution automation systems and technology, based on fault indicator information, station fault recorder information, feeders each segment of the FTU’s fault recording information and comprehensive information to achieve precise position of failure point with impedance ranging principle.Under the premise that fault indicators have been installed on every branch of feeder,according to the message recorded by FTU installed on every section switch and the message recorded by fault indicators installed on each branch line, can determine the fault section and the fault circuit; Using the fault wave record data of station and the fault wave record message of FTU installed on each section switch,calculate the vector of voltage and current after failure, according to the principle of impedance method, equation group about fault point location (fault distance)can be built by utilizing symmetrical component method,thus can deduce accurate positioning algorithm formula about short-circuit fault of distribution network.For many kinds of fault of a wide variety of distribution line,the paper has made a large amount of simulation computation by using ATP-EMTP simulation software,the result reveals that,for interphase short circuit fault in the case of single-ended measurement conditions, complex topology, fewer number of measurement points and a variety of the hybrid model,the method can locate fault accurately just by using a few fault wave record information. The impact on the accuracy of fault location,caused by feeder branch number, position of measurement point, and the size of the short circuit resistance, and other factors, was analyzed in detail in this paper.