Distributed Generation Optimal Allocation And Distribution Network Reconfiguration

The distribution system change from passive network to active electric network after the distributed generation (DG) connected to the system. It changes the flow, losses and the node voltage of the network and affects the safety and economic of the operation. The distribution reconfiguration can reduce the losses, improve the voltage and ensure the operation of the system economically through the branch switchs. Such it is important to study the optimal allocation of DGs and make good use of the network reconfiguration to realize the economical operation.In order to solve the problems of optimal allocation of DGs and reconfiguration of network with DGs, the main works of the paper are as follows:â‘ Based on the analysis of operation and control of several usual DGs, their node model in power flow calculation are presented. During the handling DG units in PV node, the calculation method of compensation reactive power based on the sensitivity impedance matrix is applied. During the calculating power flow of weakly meshed distribution network, the back/forward sweep algorithm and loop current algorithm are adopted in one iterations layor in order to reduce the calculation counts. After the DGs connected to the network, the impacts of loss and the static voltage stabilization are analysed based on the program composition of the power flow.â‘¡The optimization allocation model of maximizing DGs financial benefits is presented during the DGs connected to the grid. The model considers the DGs installation cost, operation and fuel expense, the profit from reducing the power loss, the profit from the generating electricity, environment effects, subsidized income and the profit from delaying feeders upgrading. The quantum genetic algorithm (QGA) is used to search the optimal location and sizing to achieve the maximum economical benefits.â‘¢A model of distribution reconfiguration is applied in the network with no DG. In the objective function, minimization of the losses and load balance are taken into account. The quantum genetic algorithm based on the loop encoded is used to search the optimal open branch set. The algorithm has the ability to decrease probability of falling into local optimal solution and improve search performance effectively. During the encoding, the heuristic rules are proposed to minish the length of chromosome and improve optimization efficiency, while the network has many section switchs. When the algorithm results in infeasible solutions, the taboo open branch groups for the radial distribution are used to eliminate the infeasible solutions.â‘£Based on quantum genetic algorithm of distribution network reconfiguration, the method of scenario analysis is applied to resolve the wind power generation connected the grid. When the system has the wind power generation and DGs (for exmple microturbine, fuel cell) in PV node, the impacts of DGs to network reconfiguration are analysised.The proposed methods are implemented and applied into IEEE standard systems and a practical network. The calculation results show that the methods are feasible, correct and effective.