Research On Loop-closing Risk Assessment For10kV Distribution Network

With the rapid development of technology and people’s living standard, a higher demandof power quality for the electricity customers is required, and the power intermittence willimpact on production and life seriously more and more. Therefore it is particularly importantto ensure the continuity of power supply to the customers. In order to improve the reliabilityof the distribution network power supply, Foshan distribution network dispatch began to tryloop closing operation.Owing to the unobservable distribution network, many factors, such as the voltage andphase angle differences between the loop-closing switch, the complex operating parameter ofthe distribution line, and the unpredictability of changing the main power network operationmodes, will affect the loop closing operation. The above factors would result in complexity tothe loop closing operation, and maybe produce huge circulating current and lead tomalfunction of the overcurrent protection of the distribution lines, and then affect the powersupply for the customers. Currently, State Grid and China Southern Power Grid, as well asabroad grids, develop much exploration on loop closing operation generally concentrating inthe areas of theoretical calculations. The exploration methods are generally monotonous andthe results differ considerably from the quantitative calculation and actual loop-closing result.These differences may result in misleading decision to loop closing operation.This paper does research on the Foshan power grid situation, mainly includes:1) Starting from the structure characteristics of regional power network, this paper analyzedand presented10kV loop closing operation types. Based on it, the paper proposed calculationmodel of the loop closing operation, and the calculation model can be simplified in actualapplication, which can simplify the quantitative calculation of large parameters to quantitativecalculation of the simplified network and provide references to loop-closing risk assessmentthrough the possible consequences multiplied by the probability of occurrence.2) According to the situation of Foshan10KV Distribution network and the mass data analysis,it presented six types of loop-closing calculation program and calculate the success rate ofdifferent loop-closing programs to estimate the loop-closing operational risk assessment forFoshan10KV Distribution network integrally.3) It stated loop-closing influencing factors and then gave some meaningful quantitativeconditions to loop closing operation. Combined with engineering practical problems, thispaper gave gradual correction to the various elements of the risk assessment and proposedsuitable risk assessment methods to Foshan10KV network loop closing operation, whichcould provide advice and help for promoting the loop closing work.