Active Distribution Network Reconfiguration Method With Flexible Load Participation

Distributed generation plays an important role in power distribution system as an aid for traditional power supply.However,with the large number of distributed generations connected to the grid,it has a great influence on the structure and operation mode of traditional distribution system,and hence its name-active distribution network.The more complex components of distribution system are,the higher requirements for its operation.The components of distribution system are becoming more and more complex,and the requirements for its operation are becoming higher and higher.The Operation mode of active distribution network considering the optimization and interaction of "source-network-load-storage" has become an inevitable trend.Therefore,combining flexible load control with active distribution network reconfiguration is very important both theoretically and practically to the optimization of normal operating condition and the development of solution for failure state.In this thesis,the optimal reconfiguration of active distribution network under normal operation and the fault reconfiguration under fault condition(i.e.islanding partition)were studied.The flexible loads in active distribution network have been studied in this thesis.According to characteristics of interaction with distribution system,they were classified as active loads(which can interact with the distribution system in two directions)and adjustable loads(which can only receive one-way dispatch of distribution system).According to their respective operation mechanisms,load models were built to optimize reconfiguration of active distribution and fault state.Considering the optimization of dispatching,with minimum active power loss an optimal reconfiguration model of bi-layer distribution network which has inner and outer layers was established.The two layers of the proposed bi-layer method are combined in every iteration,at each iteration the reconfiguration scheme is obtained by solving a binary optimal model in the outer layer,and the flexible loads are optimized in the inner layer.So,the optimal network topology and flexible load scheme are obtained at the same iteration.The effectiveness of this method has been verified by simulation,and the results show the importance of flexible load in optimal reconfiguration of active distribution network.The simulation models of different scenarios with different kinds of flexible loads were established respectively,and the results show that the effect and scope of application of flexible loads in islands.A real-time dynanic islanding partitioning strategy for active distribution network under extreme fault condition considering"source-network-load-storage" interactive scheduling based on heuristic algorithm was proposed.The fault state is the interruption of the connection between the distribution and the transmission system.And the electricity is unable to be obtained from the large power grid to distribution network.Real-time dynamic partition of distribution system in fault period is carried out in accordance with a fixed time scale.Using dispatching flexible load and grid reconfiguration in active distribution network to respond to the output of distributed generation,the distribution system during the fault period can be more reasonable and efficient in dynamic partition.The importance of flexible load in islanding partition of active distribution network was demonstrated by simulation.Numerical examples show the effectiveness of the proposed strategy in special application environment.