Double bus failure protection based on zero negative sequence power directional element discrimination

Abstract After the fault circuit breaker at end of long line large mode operation system fails, composite voltage sensitivity 220 kV and above double bus connection failure protection is insufficient, release complex locking function needs to be switched on off manually, which cannot automatically adapted after changes. To solve this problem, compound logic cancelled, zero negative sequence power direction discrimination used simplify startup circuit, improves adaptability reliability under various operating conditions.