A two-stage optimal strategy for flexible interconnection distribution network considering the loss characteristic of key equipment

Abstract

The flexible interconnection distribution networks (FIDN) based on soft open points (SOP) provides an opportunity to improve the economy and reliability of distribution networks. However, the existing optimal strategies have mainly focused on line power loss reduction, and the loss characteristic of SOPs and distribution transformers is ignored. Therefore, the capability of reducing total power loss for the existing optimization strategy needs further improvement. Thus, based on SOP's locating, sizing and optimal operation, a two-stage optimal strategy for FIND is proposed considering the loss characteristic of key equipment including SOPs and distribution transformers. Firstly, considering the transformer equivalent loss model and different load states, an improved loss sensitivity model is proposed to determine the optimal access location of SOP. Further, the SOP’s capacity is designed by the total cost optimization model. Secondly, based on the loss characteristic of key equipment, the optimal operation strategy is proposed to reduce the total power loss of FIND while realizing optimal economic area operation of transformers. Finally, the case studies were performed on a FIND test system with 22-bus and 15-bus to validate the proposed two-stage optimal strategy, and the results of the case studies show that the economy of FIND is greatly improved.