Optimization Of Capacity And Location Of Interconnecting Converter In Hybrid AC/DC Microgrid

With the gradual depletion of fossil fuels and the increasingly serious of environmental pollution,the development of clean energy power generation is a new direction of the future development of electric power.To avoid many drawbacks of distributed generation,the microgrid with high efficiency and high controllability has been widely used in the world.The hybrid AC/DC microgrid is a new networking form of microgrid which integrates the advantages of AC microgrid and DC microgrid,and it's the focus of microgrid research.The optimal allocation of interconnecting converter can not only guarantee the power exchange reliabilit y between AC microgrid and DC microgrid,but also will reduce the investment cost,improve the load power supply reliability and increase the clean energy utilization,which is of great significance to the preliminary planning of hybrid AC/DC microgrid.Based on the key technologies of hybrid AC/DC distribution network which is supported by “863” Program,this paper studies the optimal allocation method of interconnecting converter in different scales,different topologies and different reliability requirements.The content is mainly divided into three parts as the capacity optimal allocation at the known interconnected location,the interconnected location optimal allocation at the known capacity and the coordinated optimal allocation of capacity and interconnected location.Firstly,for hybrid AC/DC microgrid with known the interconnected location of interconnecting converter,the principles of capacity optimal allocation which satisfies the power exchange requirement between AC microgrid and DC microgrid,meets the power supply requirement of important load and meets the needs of microgrid expansion are proposed.For large-scale,high reliability requirements system and small-scale,low reliability requirements system,two capacity optimal allocation methods of interconnecting converter with different constrained conditions is put forward.The simulation results show that the capacity optimization method proposed in this paper is feasible.And the demand of power exchange,the cost of interconnecting converter and the loss of load outage have a direct influence on the optimal capacity.Secondly,for the complex topology of hybrid AC/DC microgrid with known interconnecting converter capacity,considering the economic indicators and technical indicators such as system loss,connection line cost,node voltage deviation margin and branch power margin,a interconnected location optimization method is proposed.The validity of this method is verified by using a 16 nodes network based on IEEE 14.The affections of the technical requirements,the transmission power distribution and the power fluctuation position on the optimal interconnect location are analyzed.Finally,the factors that affect the capacity allocation and access location selection are analyzed.The priority of capacity allocation and access location selection is given.For hybrid AC/DC microgrid with complex topology and low reliability requirement,the coordinated optimal allocation of capacity and interconnecting location is proposed,which takes the main capacity allocation and the secondary interconnected location allocation.And the effectiveness of this method is verified by a simulation example.