Reliability Analysis Of Distribution Network With Distributed Energy Resources

Distribution network analysis is one of the most important elements in power system analysis. With the large numbers of energy consumption and the aggravation of environmental pollution, the development and utilization of clean and efficient distributed energy resources become the focuses of researches all over the world. With the connection of large number of distributed energy resources to power grid, the tradistional distribution network is changing from a single source, radial structure to a multi source, gridding structure. Active control and Microgrid operation which used in the condition of equipment’s failure and the characteristics of randomness and volatility bring great chanllenges to the model and method for reliability analysis of distribution network. Therefor, this paper propses a method for reliability analysis of distribution network with distributed energy resources and active control strategy.Firstly, large scale distribution network is divided into segments bounded by swiches and later segments are coded in order to obtain automatic fault location and partition, which improve the efficiency of distribution network reliability analysis. The paper takes comprehensive consideration of permanent repairable failure, instantaneous failure and maintenance outage to avoid the shortage of considering only permanent repairable failure. Also a model for the development of different stages of distribution automation is established. IEEE RBTS-BUS6 distribution network is used to evaluate the reliability of distribution network without distribution network, including the effects of different stages of distribution automation and different failure types on the reliability indices.Secondly, the paper establishes output models for wind generator, PV, battery and gas turbine, and for load fluctuation. In order to reflect the seasonal and regional characteristics of distributed energy outputs, ARMA model is used to predict the outputs of wind generator and PV based on the actual data, and charging and discharging models for battery are inhibited by several restrictions. In addition, Microgrid operation, load response and optimal load shedding based on Genetic Algorithm are considered in reliability analysis with distributed energy resources. IEEE RBTS-BUS6 distribution network and actual networks in Jiangsu area are tested based on sequential Monte Carlo simulation.Due to the time consuming of sequential Monte Carlo simulation, pseudo sequential Monte Carlo simulation is proposed in which non-sequential simulation is used to select failure states and sequential simulation is applied only to the subsequence of neighboring states that define the complete interruption. High accuracy and fast simulation speed of pseudo sequential Monte Carlo simulation are tested by IEEE RBTS-BUS6 distribution network case.