Distribution Network Planning With Distributed Generation Considering The Risk Of Line Overload

With the depletion of fossil oil resource and the environmental problem to be solved, as a way of development and utilization of clean and renewable energy distributed generation has been developing rapidly. However, because of the uncertainty and intermittent of the renewable energy power generation output the operating mode of distribution network is more complicated. It may waste investment of the plan based on the maximum operating condition of traditional distribution network planning.So it is necessary to coordinate the Reliability and economy of the plan in the planning stage. The risk of line overload is considered on the distribution network planning in this paper. The main research of this paper is as follows.①The distribution network programming model including distributed generation is proposed in the paper considering the risk of line overload, to make up the inadequacy of existing uncertainty planning for risk consideration. The calculation of line overload risk is measured as customer outage cost, through the introduction of the fault rate variation of network line versus current transfer. In the model, the network investment cost, the expectation of network operation and the expectation of users outage costs are taken as the objective function, while the safe operation of the distribution network as constraint conditions. The analysis show that the reliability and economy of the network feeder plan can be reasonablely balanced when the risk of lines overhead are considered, and the planning scheme is choosed on the basis of user outage cost quantitatived.②An infeasible solution restoration method is proposed based on Kruskal algorithm in this paper, considering the low efficiency of the present infeasible solution restoration method when the distribution network programming problem is solved by intelligent algorithm. This method can make full use of existing chromosome evolution information of infeasible solution and then complete the repair of infeasible solution.③On the basis of the above study, a new coordinated planning model for distribution network integrated DG is proposed considering the risk of the limit line. In this model, the cost of investment and maintenance of equipment, the expectation of system power loss cost and customer outage cost, the expectation of power purchase cost, the expectation of environmental cost of DGs and the yearly environmental subsidies are taken as optimal objective functions, while the penetration of DG as constraint condition. The example analyses the influence of the risk of line overload and renewable DG power subsidies on the planning schemes. The results show that reliability and economy of the planning scheme can be more objectively while the risk of the line overload considered in the planning model for distribution network with DG.