Research On Active And Reactive Power Coordinated Optimization For Distribution Network With Distributed Photovoltaic

The output of distributed photovoltaic has high randomness and uncertainty.A large number of grid-connected distributed photovoltaic will lead to problems such as node voltage and line power exceeding the limit.In order to reduce the impact caused by the large number of grid-connected distributed photovoltaic on distribution network,more and more energy storage systems are connected to distribution network.Distributed photovoltaic has a certain reactive power output capability and can participate in reactive power optimization for distribution network.Energy storage system has excellent active power regulation performance and can optimize the active power in distribution network.In order to maximize the power supply quality and operation economy of distribution network,this paper combines the regulation and control of energy storage system with reactive power optimization method for distribution network,carries out active and reactive power coordinated optimization for distribution network with distributed photovoltaic,and proposes an algorithm for solving the active and reactive power coordinated optimization model.Firstly,the related theory of photovoltaic power generation system is analyzed in this paper,and it is pointed out that distributed photovoltaic has a certain reactive power output capacity.It is necessary to make full use of its reactive power and combine it with other reactive power compensation devices in distribution network to optimize the reactive power in distribution network better.Secondly,the influence mechanism of distributed photovoltaic access to distribution network on voltage and loss is analyzed,and the influence of distributed photovoltaic on voltage and loss of distribution network under different active and reactive power output is simulated and analyzed.The results show that the voltage and loss of distribution network are determined by both active and reactive power flowing in the line,and the coupling between them is very strong.Therefore,in order to maximize the power supply quality and operation economy of distribution network,it is necessary to optimize and control the active power flow in distribution network while optimizing the reactive power in distribution network.Then,the particle swarm optimization mechanism is integrated into the cuckoo search,and its shortcomings are improved.Four commonly used test functions are used to test the optimization performance of the improved algorithm.The results show that the blindness of the improved cuckoo in the search process is greatly reduced,and the convergence speed and solution accuracy are improved obviously.Finally,the active and reactive power coordinated optimization model of distribution network with distributed photovoltaic is established by combining the regulation and control of energy storage system with the reactive power optimization method for distribution network,and the reactive power optimization and active and reactive power coordinated optimization for the modified IEEE33 node distribution system are carried out respectively by using improved cuckoo search.The results show that compared with unilateral reactive power optimization,active and reactive power coordinated optimization can not only improve the loss and voltage deviation of distribution network better,but also reduce the rate of light abandonment to a certain extent,and improve the ability of power grid to absorb renewable energy.