Distribution Network Reliability Evaluation Incorporating Distributed Generation

There is a direct relationship between the distribution network reliability and the user reliability, for the distribution network system at the end of the network is connected with the users directly. About 80% power failures is caused by the fault of distribution network. With the rapid increasing in power demand, the world is watching the distribution network reliability which demand is high today. Distribution generation is one of the important electric system developing trend and the significant constitution of smart grid and strong grid with the energy crisis and environment problem, for its power-cleanly and environment-friendly. Most Distributed Power output are volatile, and distributed power access changed the original distribution network topology, therefore the distribution network reliability also ushered in new challenges. An accurate assessment of the distribution network reliability containing distributed generation which will provide theoretical support for distribution systems planning, construction and operation, promoting the development of new energy sources.On the basis of studies of the distribution network reliability evaluation theory, element, user, system reliability indices, reliability model, the failure mode are given. Choosing the Monte Carlo simulation method after comparing two types of distribution network reliability evaluation method. A detailed description of the Monte Carlo simulation design ideas using which to design Monte Carlo simulation program, including elements’ normal working hours and fault repair time is exponentially distributed. By an example of the distribution network reliability quantitative analysis, and compared with the results of the resulting analytical method to verify the correctness of the method used in this paper.After the distributed power access, and network mode, island operation modes are studied, the reliability model and the of distributed power island model are given. Using Weibull distribution to describe wind speed, wind turbines draw electrical power output model is made. Studies have shown that wind turbines rated wind speed is greater than the average wind speed, to improve the success rate of the island operation is not obvious, by increasing the rated capacity of the unit simply. Monte Carlo simulation program of island loads reliability was designed, in which Load model using normal analog and islands in full operation, load shedding and stop running, based on to powerload matching.Numerical example using RBTS-bus6 model which containing the wind power is made. Using previously designed power distribution network reliability Monte Carlo simulation, eight programs were designed for different wind turbine rated capacity and storage battery capacity. The results show that distributed power to the load point of failure rate, an island outside point of failure downtime is no improvement, but the load point within the islands’ outage time improved significantly; increasing wind turbines rated capacity, the load point reliability improving is not obvious; increasing the proportion of energy storage battery capacity of distributed power to the load point reliability improvement is remarkable.