Research On Planning,Design And Optimization Configuration Of AC/DC Hybrid Microgrid

The rapid development of high proportion of renewable energy and DC load brings great challenges to the traditional power grid;AC/DC hybrid microgrid can effectively overcome the above difficulties due to its unique structural characteristics and control advantages.In the planning stage,how to better meet the load demand and realize the large-scale distributed power supply on-site consumption in the AC-DC hybrid micro-grid needs to be solved.Based on the basic structure of AC/DC hybrid microgrid,this paper conducts an in-depth study on the design and optimization of AC/DC hybrid microgrid.This paper constructed as following four aspects: AC/DC hybrid microgrid optimization configuration,distributed generation capacity and site optimization planning,cooperative planning of hybrid microgrid and AC/DC distribution network,and AC/DC hybrid microgrid cluster optimization planning.The specific work content is as follows:(1)This paper proposes an optimized planning method for AC/DC hybrid microgrid considering microgrid expansion.Firstly,based on the AC microgrid load demand and expansion planning,two microgrid expansion planning schemes are proposed,namely pure AC microgrid expansion and AC/DC hybrid microgrid expansion.Secondly,based on the above options,an AC/DC hybrid microgrid optimization planning model with distributed generation,converter,line economic cost and system loss as the objective function is established.The model considers both the converter and the line factor,making the planning results more reasonable.Finally,the CPLEX optimization software is used to solve the mixed integer linear programming.Under the condition of DC load rate change,the optimal configuration results of different schemes are analyzed and their advantages and disadvantages are compared.(2)In this paper,a distributed power supply location and capacity optimization planning model for AC/DC hybrid microgrid is established.Taking into account the load demand and equipment failure during the expansion of the microgrid,the Monte Carlo sampling method is used to establish the uncertainty model of the load and equipment(lines,converters,transformers,etc.).A distributed power source location and capacity optimization planning method aiming at minimizing investment cost,load blackout economic cost and system loss cost.Based on the above model,the Pareto optimal solution set is obtained by using CPLEX optimization software,and the optimal solution of each target is obtained by using the fuzzy membership function.The distributed power access location and access capacity optimization configuration results of microgrid expansion are obtained.(3)A cooperative planning method for AC/DC hybrid microgrid and AC/DC distribution network is proposed.Firstly,based on the grid structure of AC/DC distribution network,the typical structure of AC/DC hybrid microgrid and AC/DC distribution network interconnection is designed.Secondly,based on the target cascading analysis method,the optimal configuration model of AC/DC distribution network and AC/DC hybrid microgrid is established respectively,and the coupling relationship is established through the power interaction between microgrid and distribution network.And the distributed power configuration results are obtained through parallel collaborative planning analysis.(4)In this paper,an AC/DC hybrid microgrid group network architecture is proposed based on the concept of cluster.A two-layer AC/DC hybrid microgrid group optimization planning model is established.The upper layer model considers two factors: node coupling degree and power balance degree to achieve the goal of dividing the hybrid microgrid cluster into targets.The lower-level optimization configuration model aims at investment cost,operation and maintenance cost,and minimum purchase and sale cost.Using optimization software analysis to obtain cluster partitioning and optimization configuration results,achieving the goal of improving regional grid tightness,distributed power supply local consumption,and reducing system cost.The optimized configuration planning and optimization configuration model of AC/DC hybrid microgrid established in this paper provides theoretical support for the planning problem of smart grid.At the same time,it has certain reference significance for the orderly grid connection of high-renewable renewable energy and the coordination and optimization planning of “source-network-load-storage” of microgrid.