The Evaluation Of Distribution Network Reliability Taking Into The Load-off In The Case Of Voltage Sag

The paper does some research on the evaluation of distribution network reliability, which put forwards to a method to evaluate distribution network reliability considering load-off in the condition of voltage drop when a feed is in fault or the voltage sag of bus bar. The bayesian network is also used to decide which feed is most important to the reliability of distribution network. The main content is as follows:1) On the basis of FEMA(failure models and effect analysis), it is shown that the minimal path method is able to evaluate distribution network reliability quickly and exactly, not taking into the structure of the network.2) Power flow calculation for distribution network is very important to the reliability evaluation. The back/forward sweep algorithm based on branch current is proved effective.3) Paper proposes a method to judge whether the sensitive load is load-off under the voltage sag of bus bar. According to fault area algorithm , it can calculate the frequency and time of load-off.4) Paper presents to using the bayersian network to confirm which feed is most important to the reliability of distribution network.5) On the basis of research above, the paper makes an all-round evaluation of a practical distribution network. The results show that it more agrees with the facts and takes into more factors. So the all-round evaluation can be used to improve the reliability of distribution network effectively.