Distribution System Reliability Assessment Methodology And Its Implementation

Aiming at the medium voltage network of the city, the subject designs the algorithm and develops the forecasting and evaluating software. The key factors which influent the power distribution reliability can be found out by using the system. And the measures to improve the power distribution reliability can be provided.This article brings forward an algorithm which combines the stratification algorithm with the FMEA (Failure Mode and Effect Analysis). According to the stratification, distribution network is divided into three layers. There are distribution network, transformer substation and feeder line. Further more, it decouples the feeder line by usable coefficient of the link Iine. The FMEA is applied to the feeder line layer. It enumerates the power failure malfunctions to get the power failure time and malfunction times. Then the algorithm gets the reliability index of the distribution network.The system proposes a new design in software. The graphic interface is divided into left view and right view. The left view expresses the stratification model of distribution network-transformer substation-feeder line. The right view offers the special drawing tools. So it can input the topology graph conveniently and quickly. According to the figures and correlative parameters, the software analyses the topology structure and builds the manifold tree structure to calculate the reliability index. In addition, an input interface is provided to input the statistical data of the factors that infect the reliability of distribution network, calculate the reliability index of the distribution network, create report forms, display and compare expected index and statistical index. In the end, method to improve reliability is proposed at the assistance of the system.The running circumstances attest the system that not only forecast the reliability index of the distribution network quickly but also find out the weak tache of the distribution network by simulative changing the graph. It provides a powerful tool for distribution system planning and reconstruction.