Study On Reactive Power Optimization Of Distribution Network With Distributed Generation

Distributed generation has the ability to output both active power and reactive power to the distribution network.The reactive power optimization of distribution network is carried out by regulating the reactive power output of distributed generation and reactive power compensation equipment,which can reduce the active loss of distribution network and improve the voltage quality of distribution network.However,the power output of distributed generations such as photo voltaic and wind power generation is easily influenced by the natural environment,which brings great challenges in the reactive power optimization of the system.Based on it,the thesis studies the algorithms for reactive power optimization of distribution system with distributed generation and dynamic reactive power optimization methods.The main contents are below.(1)Firstly,the thesis studies the grid-connected interface forms and characteristics of power output of common distributed generation.the power flow calculation of the distribution network with distributed generation is studied.According to the demand of power flow calculation for reactive power optimization of distribution network with distributed generation,the forward and backward substitution method is improved.Finally,the influence of the power output of distributed generation and the location of grid connected bus of distributed generation on distribution network is analyzed.The results show that the distributed generation should be configured with reasonable capacity,and the farther location of the grid connected bus of distributed generation is from the root bus,the better effect of reducing active loss of distribution network and supporting distribution network voltage.(2)The reactive power optimization model of distribution network with distributed generation is established.The thesis proposes an improved artificial fish swarm algorithm which improve the convergence speed of the algorithm and overcome shortcoming of the algorithm easily falling into the local optimal solution by reconstructing the behavior pattern of artificial fish and introducing the autonomous diffusion mechanism of fish swarm..The simulation prove that the proposed algorithm can solve the reactive power optimization problem in distribution network quickly and effectively.(3)The thesis proposes a dynamic reactive power optimization method.First,the reactive power optimization model is established.And the optimal switching time and capacity of capacitors can be obtained by solving the model.Then make full use of distributed generation to correct the reactive power distribution of distribution network in time.It make the distribution network keeping the state of optimal reactive power flow in actual operation,and reduce power loss.of the distribution network effectively.Finally the simulations are carried out to validate the effectiveness of the dynamic reactive power optimization method.