Multi-objective Distribution Network Reconfiguration Considering The Variation Of Wind-solar-load

With the rapid development of China's economy,the overall demand for electricity is increasing year by year.However,the non-renewable energy represented by oil and coal will be exhausted in the 21st century,which brings great challenges to the field of energy security.In order to solve the predicament of resource shortage,improve power quality and promote the balance of power consumption,China has been vigorously promoting the construction of new energy generation based on wind power and photovoltaic power since this century.Due to the volatility of new energy,large-scale grid connection will have a great impact on the safe and stable operation of the entire power system.In order to ensure the safe operation of power system,reduce network loss and equipment usage cost,a multi-objective distribution network reconfiguration method based on Grey Wolf algorithm is proposed in this paper.Its specific work includes the following aspects:Firstly,it is treated as PQ(V)and PI nodes according to the operation characteristics of wind and photovoltaic.The hierarchical forward-backward power flow algorithm is used to study the influence of different locations and outputs of wind and photovoltaic power supply connected to distribution network on system voltage and network loss.The results show that when the wind and photovoltaic access points approach the load position or the power output is less than 2 times of the load,the system loss is smaller and the voltage is significantly improved,which provides a basis for the research of the optimization and reconfiguration of wind and photovoltaic power supply into distribution network.Secondly,a binary grey wolf optimization algorithm with fewer parameters and faster convergence speed is adopted to research the distribution network reconfiguration with minimizing system loss.The problem of closed-loop operation and islanded operation in the process of distribution network reconfiguration is solved by using branch integer coding strategy.The validity of the algorithm is verified by using the IEEE-33 nodes and simulated in 105-bus actual distribution system.The simulation results show that this method can reduce network loss and improve power quality effectively.Finally,the multi-objective grey wolf optimization algorithm is proposed to solve the problem of multi-objective reconfiguration for optimal network loss and minimum switching operations in power grid.The congestion distance measure and phase-out strategy are adopted to make the obtained Pareto solution sets meet the requirements of diversity and uniform distribution.According to the requirement of reconfiguration time and number of times in a day by dispatching department,a time division strategy is proposed to divide the next day into three periods and reconstruct them separately.The Pareto solution of each time period is evaluated comprehensively by using the method of entropy weight,and the best three reconstruction schemes in a day can be obtained.The simulation results show that this method can reduce the network loss and equipment usage cost simultaneously,and improve the economic operation cost of the power grid effectively.