A Multi-objective Optimal Phase Swapping Research For Distribution Networks With DG

As the global fossil energy inceasingly drying up, the distributed power which use renewable energy with its flexible and efficient generation mode that gradually plays an important role in the electric industry. With more single phase or two phases distributed generations(DG) gradually access to distribution nerworks, the problem of three-phase imbalance will be more serious. The three-phase imbalence in distribution nerwork with distributed power willcause many problems such as three-phase asymmetrical voltage,overrun neutral line current and increased line loss. As the three-phase asymmetry degree in the distribution network increases,the ralatively capacitive current will be more imbalenced. This problem will affect the operation which is safe and stable in power grid.Now solve the prolem without considering the realistic background that the distributed power supply is gradually access to the distribution network and also the commutation strategy has failed to consider comsider power loss, and the residential electricity loss is difficule to accurately assess. In order to solve this problem and avoid frequent phase swapping, a new optimal phase swapping model with multi-objective of reducing the overall three-phase imbalance degree and the total number of commutation lines for distribution networks with DG was built, which various DG and the node load curve characteristics are considered. By introducing the interaction between molecules into the differential evolution algorithm, a new multi-objective molecular differential evolution algorithm is constructed to solve this model. The new algorithm can automatically maintain the diversity of individuals by using the principle of molecules closer repulsion greater automatically in the process of evolution, and can guarantee searching speed and avoid premature, to achieve efficient depth optimization.Finally, the simulation based on the IEEE-34 note improved system was carried out to verify the validity of the proposed multi-objective optimal phase swapping strategy and the superiority of the molecule differential evolution algorithm.Result was presented to verify the effectiveness of the differential evolution algorithm that can effectively alleviate the contradiction between the calculating speed and depth. The phase swappingstrategy based on the mothod which was prosed in this article can reduce the total numbers of outage lines and also can reduce power loss and three-phase imbalance and alleviate the asymmetry of the three-phase voltage.