Feasibility Study of Using Flexible Substations in Distribution Systems in China

Distribution systems are confronted with increasing power supply demands of diverse loads, integration convenience requirements of multiple generators, and interconnection needs of distribution networks. The flexible substation, based on advanced power electronic technologies, is one effective solution. It integrates the functions of transformers and various converters, and obtains flexible control abilities. It is significant to conduct a comprehensive feasibility study of utilizing flexible substations in distribution systems in China. Basic structure of the flexible substation is stated, and its multiple using patterns and characters are put forward. Issues including application scenarios, location selection, capacity determination, storage allocation, protection setting, insulation coordination, information communication and power quality for using flexible substations in practical distribution systems in China are proposed and discussed. Case study on Zhangbei flexible substation demonstration project design is conducted, and the results indicate the feasibility and flexibility of the flexible substation application.