Research On Reactive Power Optimization Of Distribution Network With Distributed Generation

In order to build a green and low-carbon energy system and promote the realization of the " Carbon Peak and Carbon Neutrality " process,distributed power sources based on distributed wind power and photovoltaic have developed rapidly.After the distributed power is incorporated into the distribution network,it can inject both active power and reactive power.Therefore,the reactive power optimization of the distribution network by adjusting the reactive power generated by the distributed power supply and the reactive power compensation device can maintain the stable and economic operation of the distribution network.However,with the increase of the penetration rate of distributed power grid connection,it will not only facilitate the power grid,but also have a certain impact.Therefore,it is of great significance and value to study the reactive power optimization of distribution network with distributed generation.In order to solve the problem of reactive power optimization of distribution network with distributed generation,this paper proposes a reactive power optimization scheme of distribution network considering the daily load at different times and the changing output level of distributed wind power and photovoltaic.The main research contents are as follows:Firstly,a multi-objective reactive power optimization model of distribution network with distributed generation is established.An improved differential evolution algorithm is proposed.By improving the initial population and adaptive parameters,the accuracy of the algorithm is improved and the algorithm is avoided to fall into local optimum.Through the example analysis,the feasibility and effectiveness of the proposed algorithm to solve the multi-objective reactive power optimization problem of distribution network with distributed generation are verified.Then,based on the multi-objective reactive power optimization model,the equivalent daily load curve is segmented based on information entropy,and two optimization schemes are designed based on whether the node voltage exceeds the limit.If the node voltage exceeds the limit,the distribution network is quickly partitioned by the electrical distance,connectivity and area diameter between the nodes.According to the results of the partition,the reactive power output of the distributed power supply and the switching of the reactive power compensation device in the voltage violation area during this period are adjusted.The improved differential evolution algorithm is used to optimize the local reactive power and output the Pareto optimal solution.If the node voltage does not exceed the limit,the global reactive power optimization of the distribution network is solved during this period,and the reactive power output of all distributed power sources and the switching of reactive power compensation devices are adjusted to obtain the Pareto optimal solution.The IEEE-33 and IEEE-69 node systems are used as examples.The results show that in the case of node voltage exceeding the limit,the partition reactive power optimization can obtain the optimization effect similar to the global reactive power optimization by only adjusting the reactive power compensation device in the area where the over-limit node is located,and can obtain a better node voltage distribution curve than the global optimization.In the case of node voltage not exceeding the limit,the distribution network after global reactive power optimization is better than before optimization in network loss and node voltage level.