Research and application of 220 kV main connection mode of two section single bus with tow circuit breaker
GAO Yadong1,2, GAO Meijin1,2, CHEN Fei1,2, LOU Bingwu1,2, JIN Guosheng1,2
（1.State Grid Zhejiang Economic Research Institute, Hangzhou 310008, China; 2.Zhejiang Electric Power Economic Research Institute, Hangzhou 310014, China）

Abstract: Aiming at the adaptability of doublebus with the application of low maintenance and high reliability bus(GIS, DCB and GIL bus), a new main electric connection scheme for a two section single bus with tow circuit breakers was proposed for the designed capacity of three main transformers in a 220 kV substation. Two main transformers were able to be maintained in operation with this mode, in case a power outage occurs on either bus. The connection mode of two section single bus with tow circuit breakers and the one of double bus were compared and analyzed by using the failure mode and effects analysis (FMEA) method, in the three aspects of reliability, flexibility and economical efficiency. The results indicate that the connection mode of two section single bus with tow circuit breakers has great value in engineering applications, which can increase the reliability and reduce the cost of investment. The flexibility required for daily operation and future expansion can be taken into account at the same time.
Key words: single bus with tow circuit breakers in system; the reliability; the flexibility; the economical efficiency