Research On Multi-objective Planning And Control Partition Of Active Distribution Network

In 2008,the International Council on Large Electric Systems(C6)C6.11 project team proposed the concept of active distribution network.Active distribution network could control the distributed energy systems accessed in distribution network and manage power flow actively by the flexible network topology,which achieves the the"active" control and "active" distribution of power.The proposition of active distribution network marked a change of operation and control mode of distribution network,and it is an important part of future development of smart grid.The active distribution network with distributed generation can deal with the high-permeability of distributed generation and give full play to technical advantages of active distribution network,which improves the operatrion reliability and economy of distribution network.The multi-objective planning of active distribution network helps to balance the various objective s and achieve the best operation condition of distribution networks.Conducting the partition control according to the network topology can narrow the control scope and improve the system controllability,and it can deal with different types of distributed energy systems.It does not need to establish a complex system model and reduces the complexity of calculation degree,so that the power system could maintain a good scalability which is significant for the construction of strong power grid.This paper focuses on the planning and control paritition of active distribution network which has completed the following work:Firstly,this paper elaborates the concept,structure,function and management mode of active distribution network systematically and expatiates on the correlation and difference between active distribution network and distribution network with distribution generation.It analyzes the influence of distributed generation brought to the distribution network from the aspects of planning,operation and protection,and discusses the active distribution network with distributed generation systematically.Secondly,this paper analyzes the existing planning method of active distribution network and establishes a multi-objective hierarchical planning model which considers the operation reliability and economy of active distribution network.The upper planning model preselects the installation location of distributed generations according to the position coefficient.The lower planning model sets up an economic objective function containing equipment cost of distributed generations,network loss cost,annual electricity purchase cost and government subsidy.Particle swarm optimization algorithm is used to calculate the installation location and installation capacity of distributed generations,which conducts the economic optimization of distribution network under the premise of power supply reliability.Finally,this paper studies the control partition method under active management mode of active distribution network by means of complex network theory.The electrical distance is defined and the weight matrix is established to provide the measurement unit for the voltage control partition of active distribution network.The results of voltage control partition are evaluated by modularity.Improved particle swarm optimization algorithm is used to calculate and new coding scheme and updating strategy are proposed to improve the convergence speed and save the storage space.Take IEEE 33 nodes distribution system and IEEE 69 nodes distribution system as examples to verify the validity and rationality of planning model and partition method.The complexity of active distribution network structure and function makes the characteristics of distribution network more and more close to transmission network,and the analysis method of transmission network is also gradually applied to distribution network.The study of planning and control partision for active distribution network helps to improve the management efficiency and provide the reference for management and strategy of active distribution network.