Research on Interconnection Structure and Control Technology of Flexible Distribution Network Based on Soft Open Point in Parallel With Interconnection Switch

Abstract

The soft open point (SOP) are used to replace the traditional interconnection switch in distribution network, which can improve the controllability, flexibility and renewable energy capacity of distribution network, and realize economic operation of regional distribution network. Compared with the traditional interconnection switch, SOP is expensive and occupies a large area. The location and capacity of SOP can be optimized by planning algorithm to reduce its comprehensive cost without considering the condition of load transfer. However, the main function of interconnection switch is load transfer, if this demand cannot be met by SOP, the popularization and application of SOP will be limited. Therefore, a flexible interconnection scheme of distribution network based on SOP in parallel with interconnection switch was proposed, considering the economic planning and the demand of load transfer, to reduce the additional cost of load transfer from SOP, and support the large-scale application of SOP in distribution networks. Based on this scheme, a smooth switching control strategy was proposed to realize the seamless switching of SOP control mode and no phase difference closing of parallel interconnection switch, thus reducing the voltage and current surge on SOP in the process of load transfer.