Research On Expansion Planning Of Active Distribution Network

In recent years,the distributed generation technology of renewable energy,which is represented by wind power and photovoltaic,has developed rapidly.Traditional distribution network adopts passive control method.With the increase of distributed generation access,it is unable to meet the users' safe,reliable and diversified power supply needs.Through active control and management,active distribution network can significantly improve the compatibility of renewable energy,reduce investment in upgrading distribution system equipments,improve power supply reliability and power quality of the system,and will be the development direction of smart distribution network in the future.Expansion planning of active distribution network considering load growth has an important significance to promote renewable energy consumption and improve the economy of distribution network planning and operation.In view of the above problem,this paper first introduces and analyzes the concept,characteristics,and active control & management technology of active distribution network.Secondly,taking wind turbine,photovoltaic,and micro-gas turbine as the typical representatives of distributed generation,a sequential power flow calculation model of multi-type distributed generators and loads is established.Based on this,expected scenarios of active distribution network planning are established considering the uncertainty of wind speed,radiation and load,and the Fuzzy C-Means clustering algorithm is used to reduce the number of scenarios.Then,considering four kinds of active control measures,a two-level optimization model for the expansion planning of active distribution network is established.The goal of the upper level planning is to minimize the integrated cost of investment and operation in active distribution network,and the lower level planning aims at the minimum annual operating cost of active distribution network.A hybrid algorism combining improved particle swarm optimization and predictor-corrector interior point algorism is developed to solve the planning model.Optimal compatibilization scheme of the system that meets the requirement of load growth is obtained: the optimal planning scheme composed of construction & upgrading of line,siting & sizing of distributed generators,demand-side resources allocation and corresponding operation control measures.The algorithm uses the fuzzy control method based on the node voltage and the network loss sensitivity factor to initialize the DG access location,which can effectively improve the speed and efficiency of the algorithm.Finally,the extended IEEE-33 node distribution system is selected as a simulation example to demonstrate the effectiveness and feasibility of the proposed model and algorism.