Avtive Distribution Network Transient Stability Analysis And Reconfiguration Optimization Based On Energy Function

The distribution network is located at the end of the power system,which ensures the connection between power loads and power supply,the reliability of the power supply of the distributed network is closely related to the users.During the vigorous development of power system,ensuring the high quality and reliable power supply of distribution network has become an important direction of power investment and construction.At the same time,the distributed generation technology represented by photovoltaic,wind power,fuel cell and micro gas turbine is becoming more and more mature.The growing connection of distributed energy resources brings about significant impact on all aspects of the distribution network.In this thesis,a research on "panoramic information based security defense and self-healing control method of intelligent distribution network" has been done,the main contents of the thesis are as follows:Firstly,an energy function of grid-connected distributed network is proposed to analysis the unstable energy and the transient stability of distributed power network in case of a failure.Secondly,the energy function of active distribution network is built.The active distribution network power transmission model and the inverter power transmission model are constructed at the same time.The variation of transient energy of the active distribution network in case of failure is quantitatively analyzed.Simulation experiment based on the modified 3 machines-9 nodes system is done to verify the effectiveness of the proposed model.Then,in order to improve the reliability of distributed network,a multi-objective optimization function is proposed.The energy function of weak branch is considered to measure the impact of DG configuration on system transient stability.An improved hybrid algorithm is used to solve the optimal configuration of DG,so as to avoid local optimal and fast convergence.Through the example analysis,the reasonable location and capacity selection of DG can improve the reliability of distribution network,and the validity and correctness of the proposed method in this chapter are verified.Finally,in order to ensure the safety of distribution network after reconfiguration,a multi-objective optimization reconstruction model of active distribution network based on energy function is established,and the optimized design of reconstruction structure of distribution network is carried out.The multi-objective particle swarm optimization algorithm is applied to solve the problem,and the optimization results are evaluated by using the sorting method of approximating the ideal solution.The Pareto solution set is filtered to get the optimal solution.The simulation and analysis of the actual power grid in a region of Shenyang is done,and the validity and correctness of the proposed method are verified.