Multi-Objective Operation Optimization Of Active Distribution Network Based On Flexible Multi-State Switch

With the diminishing reduction of non-renewable energy sources such as coal and petroleum,numerous intermittent distributed generators(DGs)have been involved in distribution networks,and the increase in permeability of it has brought enormous challenges to the operation of distribution networks.The three-terminal flexible multistate switches,which are controllable,are adopted to replace the traditional tie switch and to increase the flexibility of distribution network operation and control.Firstly,the power flow calculation method of distribution network with DGs is introduced in this paper,based on this,the influence on the voltage distribution and network loss of distribution network with DGs is analyzed.Then some ordinary objective functions and constraints of the distribution network optimization model are introduced,and several basic algorithms solving the optimization model as well as the advantages and disadvantages of them are briefly analyzed,among which the standard particle swarm optimization algorithm(PSO)and the advantages and disadvantages of it are emphasized,In order to avoid results be trapped in local optimum.an improved multi-population particle swarm optimization algorithm is proposed,and the performance of the improved algorithm is tested by several standard test functions.Finally the timing characteristics of distribution network operation are considered and the controllable load and the three-port flexible multi-state switch are introduced to this methodology.A multiobjective operation optimization model for active distribution network is developed,i.e.the objective functions are designed to minimize the operating cost of the distribution network and to minimize the voltage deviation in multiple periods with consideration of demand response according to the characteristics of active distribution network.The effectiveness of the proposed method is validated based on the IEEE 33-node test feeder by the improved Particle Swarm Optimization algorithm.Results show that the coordinated optimization of the flexible multi-state switch and demand response improve the distribution network voltage levels significantly,which will not only bring the economic efficiency but also improve the safety and reliability of the system.