Research Of Improving The Success Rate Of Reclosing On Synchronization Line Between Small Hydropower And Large Power System In Jiangmen Power Grid

In electrical power system, most of the breakdowns occur on transmission line(especially overhead line). In order to enhance the reliability of transmission line, reduce thepower cut time, and lessen the economic loss, and technology of auto reclosing has beenwidely used in electrical power system. According to the statistics, the success ratio isgenerally about60%~90%.Auto reclosing not only enhance power systems reliability of andreduce the loss, but also improve the level of power system transient stability. Besides,correcting the mistrip of switch or protection devices quickly is another major function.However, after the failure of synchronization lines and small hydropower split fromlarge power system，small hydro power have large power gap in dry season， while largesurplus power in wet season, and auto reclosing is hard to success for the unbalanced power.This thesis analyzes the reason for low success ratio of auto reclosing on synchronizationlines between small hydropower and large power system in Enping Power Grid, and proposessome measures to improve it. The primary coverage are as follows:In the first, the research status of auto reclosing, concepts of DG operated in isolatednetwork, problems of auto reclosing on synchronization lines between small hydropower andlarge power system, and the basic principles and related reclosing calculation setting areintroduced. Besides, the problems caused by small hydropower and the influence of smallhydropower for the rely protection and reclosing at dry season and wet season are study. Andthen, water resources distribution, power status, loads, small hydro power generation inEnping is referred. at last, the measures of reclosing at dry season and wet season whichconsider the problem of isolated networks are proposed and also the reclosing logic areimprove. The improved logic of reclosing has a good reference to the manufacturer when theydesign the reclosing, and the measures can improve the success ratio of reclosing onsynchronization lines between small hydropower and large power system, and has importantsignificance to improve the security and the reliability of the power。...