Study on Reliability of Distribution System with Unreliable Distributed Generation

摘要

Increasing insertion of distributed generations (DGs) challenges power grid security. Based on analysis of failure impact delivery which is divided into the counter-flow delivery and the direct-flow delivery, the approach of distribution system reliability evaluation is proposed. Because of no accurate value of some data in practice, interval arithmetic is introduced to calculate reliability indices. On the basis of analysis of output instability of DG, recovery probability index is used to be on behalf of the probability of island operation. Then distribution system reliability indices are calculated with this method. Case calculation of a 10kV feeder at Qingdao verifies improvement of system reliability with the insertion of DG, show that access point and island partition that play an important role in reliability of loads must be considered in scientific planning of insertion of DG.