Multi-objective optimization method for distribution system configuration using pareto optimal solution

Distribution network has huge number of configuration candidates because the network configuration is determined by state of many sectionalizing switches (opened or closed) installing in terms of keeping power quality, reliability and so on. Since feeder current and voltage depends on the network configuration, distribution loss, voltage imbalance and bank efficiency can be controlled by changing state of these switches. In addition, feeder current and voltage change by out put of distributed generators (DGs) such as photovoltaic generation system, wind turbine generation system and so on, connected to the feeder. Recently, total number of DGs connected to distribution network increases drastically. Therefore, many configuration candidates of the distribution network must be evaluated multiply from various viewpoints such as distribution loss, voltage imbalance, bank efficiency and so on, considering power supply from connected DGs. In this paper, the authors propose a multi-objective optimization method from three evaluation viewpoints ((1) distribution loss, (2) voltage imbalance and (3) bank efficiency) using pareto optimal solution. In the proposed method, after several high-ranking candidates with small distribution loss are extracted by combinatorial optimization method, each candidate are evaluated from the viewpoints of voltage imbalance and bank efficiency using pareto optimal solution, then loss minimum configuration is determined as the best configuration among these solutions. Numerical simulations are carried out for a real scale system model consists of 72 distribution feeders and 234 sectionalizing switches in order to examine the validity of the proposed method.