Study On Optimization Reconfiguration And Service Restoration For Distribution Network With Distributed Generation

It has become a trend to connect distributed generation with uncertain output such as wind power and photovoltaics to the distribution network.With the increase of uncertain distributed generation capacity connected to distribution network,how to formulate an optimization reconfiguration scheme considering the uncertainty of distributed power output is a key issue to ensure the safe and economical operation of the distribution network.At the same time,when the distribution network fails,how to formulate a service restoration plan that considers the islanding operation of distributed generation is also a problem that distribution network operators pay close attention to.In view of the above problems,this paper studies the optimization reconfiguration and service restoration of the distribution network based on the stochastic power flow calculation of the distribution network.The main research contents are as follows.1)Study on the stochastic power flow algorithm of distribution network with distributed generation.Firstly,based on the characteristics of distributed generation and load,a probability model of distributed power output and load demand is established.Then,the calculation method of stochastic power flow in distribution network is analyzed,and the principles and calculation steps of stochastic power flow of two semi-invariant methods are given.Finally,in the IEEE33 node system,the Monte Carlo method is used to analyze the above two stochastic power flow calculation methods,and a more suitable stochastic power flow calculation method is selected as the basis for subsequent research.2)On the basis of considering the uncertainty factors of the distribution network,the optimization reconfiguration of the distribution network is studied.Firstly,based on the chance-constrained programming model,a mathematical model of distribution network optimization reconstruction is established that takes into account the uncertainty of distributed generation output and load.Then,the distribution network is simplified based on the principle of optimization reconfiguration of the distribution network,and the hybrid particle swarm optimization algorithm is used to solve the optimization reconfiguration model.Finally,the effectiveness of this method is verified by simulation in IEEE33 node system and PG&E69node system.3)Study on service restoration of distribution network with distributed generation.Firstly,a topology model of the distribution system is established,and a topology analysis method of the distribution network that can quickly identify the main system topology and power loss area after a fault is proposed.Then,the islanding division problem is studied,the island load optimization model and island topology optimization method are established,the co-evolution algorithm is used for island load optimization,and the island topology is modified according to the load recovery scheme.Finally,it analyzes whether there is a tie switch branch between the power loss area and the main system,and proposes a service restoration strategy for the distribution system considering the islanding operation of the distributed generation supply,and simulates the effectiveness of this strategy in the IEEE33 node system.