A method for dead zone fault isolation and fast recovery of error cutting element under the existing 3/2 connection mode

Under the existing 3/2 connection mode, the incompletion between the configuration of the protection and transformer leads to the existence of the dead zone. When the fault occurs in the dead zone, line protection and breaker failure protection are generally matched with each other to achieve the complete isolation of the fault. This approach will make the scope of the circuit breaker to expand, and even leads to unnecessary outage of the normal bus. So it seriously affects the safe and stable operation of the system. In view of the above problems, this paper analyzes the features of the dead zone under different protective CT configuration mode, and provides a method for dead zone fault isolation and fast recovery of error cutting element. By introducing circuit breaker opening and closing state information, the method identify dead zone fault and the breaker failure effectively. At the same time, based on the information sharing in the station area, the circuit breaker can be quickly recovered by using the reclosing function of the circuit breaker, which can significantly improve the safe and stable operation level of the system.