Optimal Placement And Sizing Of Distributed Generations In An Active Distribution System Considering Effects Of Controllable Load

With the sustained growth in electricity demand and rapid development of distributed energy,conventional passive distribution network cannot meet the requirements of the environmental protection,power supply reliability and power quality.Active distribution system(ADS)which is capable of fusing and controlling several kinds of distributed resources will serve as an important development direction of future distribution technology.When doing active distribution system planning,both the contents of traditional distribution network planning and the impact of the access of distributed generations,demand response and other aspects should be taken into account.This paper focuses on the research of optimal placement and sizing of distributed generations(DGs)in an active distribution system considering effects of controllable load.Firstly,this paper presents a method of determining the candidate bus sets for distributed generation installation.Two novel indexes,Loss-Active Power sensitivity index(LPSI)and Voltage Stability Index(VSI),are proposed to identify the nodes with different attributes.Fuzzy C-means cluster algorithm(FCM)is applied to classify nodes in the distribution system,which paves the way for the optimal placement and sizing of distributed generations in an active distribution system.Secondly,on the basis of conventional optimal configuration method of distributed generations in a distribution network,combining with the characteristics of the active distribution system,this paper constructs a bi-layer distributed generation optimization model taking effects of controllable load(transferable load,load which can be curtailed,battery swap station(BSS))into consideration.The upper-layer model aims at obtaining the optimal placement and sizing of DGs connected to the active distribution system.The lower-layer model aims at calculating the optimal active power of controllable load.Robust optimization theory and box uncertainty sets are used to describe uncertainties of output of uncontrollable DGs(wind turbine and photovoltaic).Bat algorithm is applied to solve the bi-layer model problem.Finally,the analytical results for an active distribution system built on the basis of IEEE 33-bus distribution system verify the rationality of the proposed models and feasibility of the algorithm.Reasonably considering the scheduling of controllable loads while optimizing configuration of distributed generations in an active distribution network can reduce both the loss of system network and electricity cost,achieving a win-win situation between the grid and the user.Comparison with genetic algorithm(GA)and particle swarm optimization algorithm(PSO)shows and better ability of global optimization of the bat algorithm.