Optimization And Assessment Of Black-start Plan With Distributed Energy Supply Systems

Black-start is the last line of defense for the reliability of the power system.Many city grids lack of black-start units because hydraulic turbine is restricted by geographical location and diesel generator is eliminated for high pollution but poor efficiency.In recent years,the construction of distributed integrated energy supply system has gained great support from the government because it has relatively higher efficiency and less pollution.Moreover,gas turbine integrated energy supply system has excellent self-start ability and great flexibility,which makes it suitable to be black start units.In this paper,the gas turbine distributed energy supply system is considered as black-start unit,technical problems that occur in the process of black-start are analyzed by a large amount of simulation,and then technical examination model and decision support system are constructed.The important technical problems which are involved in the process of black-start are modeled and simulated using PSCAD/EMTDC simulation software.Technical problems include the calculation of transformer inrush current,cascade transformer sympathetic inrush current and transmission line switching overvoltage.The influence factors of these values are analyzed in detail.And then,this paper proposes a method which uses back propagation artificial neural network for fast amplitude determination of some technical values in the black-start plans based on distributed energy supply system.Finally,this paper establishes a black-start plan decision-making system which consists of the multi-objective optimization and the multi-attribute evaluation.In the multi-objective optimization,the optimization goals are to maximize the total time weighted generated energy of the second started units and the reliability of the black-start plan.The Group search optimizer,Dijkstra optimal path selection algorithm and the Fast amplitude determination model are employed to solve the Pareto optimal solution set with the consideration of the units and system constraints.Then,the electrical power professionals' experience is integrated into the decision-making by using Evidential Reasoning.Through the above procedures,the best solution in the Pareto optimal solution set is picked out.