Multi-objective Optimization Of Voltage And Reactive Power In Active Distribution Network Considering Solid State Transformer

The large-scale distributed power supply is gradually connected to the distribution network,and the distributed power output has a large randomness and uncertainty,which brings certain challenges to the optimal operation of the distribution network.The reactive power optimization is an important guarantee for the economical,efficient and safe operation of the power system,but the traditional on-load voltage regulation tap changer has the shortcomings of low regulation accuracy and limited safety life,solid-state transformer can realize reactive power compensation by constantly adjusting the reactive power on both sides of the original pair.In this paper,the reactive power optimization control effect of solid-state transformer is studied.The main contents are as follows:Overview of the current state of research on solid-state transformers and reactive power optimization,and the working principle of AC/DC/AC solid-state transformer is analyzed in detail,and its steady-state operation mathematical model is established.For the characteristics of solid-state transformers,the forward-backward method combined with alternating iterative method is proposed to calculate the power flow of distribution network with SST,which verifies the power flow regulation and control ability of solid-state transformer.Non-dominated sorting and congestion distance calculation are added to the new sparrow search algorithm to expand to multi-objective sparrow search algorithm,and improved strategies for population initialization,global search ability and optimal solution disturbance mutation are proposed respectively,and simulated with other classical multi-objective optimization algorithms and novel optimization algorithms on test functions to verify the feasibility of the proposed improved algorithm by comparing evaluation metrics.A reactive power optimization model which takes into account economy,safety and reliability is established.In the modified IEEE28 node system,the solid state transformer is used as the distributed power grid interface.Based on the three reactive power optimization control means,IMOSSA、MOPSO、BAS-MOSPO and MOSSA are used to find the Pareto optimal solution,and the reactive power optimization results are compared in terms of algorithm performance.The results show that the solid-state transformer reactive power optimization has good voltage stability and better economy,and also verify the superiority of the proposed multi-objective sparrow search algorithm to solve the reactive power optimization.