Optimal Allocation of Distributed Generations with SOP in Distribution Systems

The concept of flexible AC transmission systems (FACTS) that has been successfully used in power flow control could potentially benefit the distribution networks equally, in particular for supporting the integration of distributed generations (DGs). This paper considers an emerging distributionlevel FACTS (D-FACTs) device, namely soft open point (SOP) that provides both active and reactive power flow capabilities. To use distributed generations (DGs) at distribution level to accommodate local increasing energy consumption can reduce the power losses due to long distance power transmission, while maximizing the utilization of local renewable and clean energies. This paper investigates the optimal sizing and location of DG units with smart inverters assisted with SOPs in the distribution systems. To solve the non-convex and non-linear optimization problem, a fast IPOP-CMA-ES algorithm is proposed and its efficiency is validated in a modified IEEE 33-bus test system under different operating conditions. Simulation results have revealed that the optimal DG allocation can achieve up to 93.26% power loss reduction and 93.62% voltage deviation reduction, while the line congestion level revealed by load balancing index has significantly dropped from original 6.26 to 0.35 only.