Research On Optimization Of Service Restoration For Distribution Network Considering Active And Reactive Power

Power outages in distribution network which is the link between the power system and the users will cause serious economic losses and social impacts,so the power supply in non-faulty outage areas must be restored as soon as possible.With the gradual increase of the penetration of distributed generators in distribution network,the rational use of distributed generators after the fault of the distribution network can provide emergency power supply for loss of load,reduce the loss of users and improve the flexibility of distribution network.Existing researches on service restoration with distributed generators in distribution network mainly focus on how to divide the distribution network into multiple microgrids to restore as much key load as possible.However,the existing research mainly considers the active power balance,but ignores the optimal scheduling of reactive power during power recovery.Due to the high R/X ratio of the distribution network,ignoring the scheduling of reactive power may result in a severe drop in voltage at some nodes.In addition,considering the uncertainty of distributed power sources and loads,the lack of reactive power support can lead to voltage instability within the microgrid,and even lead to the collapse of the microgrid.Therefore,this paper proposes a service restoration strategy considering the optimization of active and reactive power.The main tasks are as follows:First,an optimization model for service restoration of distribution network based on active power balance is established.With the maximizing the weighted load recovery as the optimization objective,the author considers node security constraints,network connectivity constraints and distribution network power constraints for establishing a distribution network recovery model.The model is solved by commercial CPLEX and simulated in IEEE 37-node system to verify the model effectiveness.Secondly,a service restoration model of distribution network considering active and reactive power coordinated dispatch is established.The operating characteristics of the energy storage systems,static VAR compensation and capacitors banks are analyzed,and corresponding mathematical models are established.Then,based on the optimal scheduling of each reactive power control equipment,a service restoration model of distribution network is established with the minimum load shedding and minimum voltage deviation as the objective functions.Finally,the model is solved by commercial CPLEX and simulated in IEEE 37-node system to verify the model effectiveness.Thirdly,Considering the influence of the uncertainty of renewable energy output and the randomness of load fluctuation on the distribution system,A stochastic optimization model for service restoration in distribution network with active and reactive power coordination is established.Based on the scenario probability method,multi-scenario construction of the load and the output of renewable energy units is carried out,and the uncertainty problem is divided into multiple scenarios for analysis through scenario reduction.Then,with the minimum load shedding and the minimum voltage deviation as the objective function,considering the constraints of distribution network topology,distribution network power and controllable equipment coordination and scheduling,a stochastic optimization model for service restoration in distribution network with active and reactive power considering the uncertainty of renewable energy output and load demand is established.Finally,the model is solved by commercial CPLEX and simulated in IEEE 37-node system to verify the model effectiveness.