PURPOSE:To enable high-speed working to be obtained immediately after an accident is generated, by storing stopping output during a specified period, and by contriving the stopping output not be generated with data before the detection of the accident, when the value of an accident detecting function is a specified value or larger. CONSTITUTION:Terminal current data Dj are used, and by a suppression function computing means 1, a suppression function f(r) is produced. Besides, differential current data Dd are used, and by a differential function computing means 2, a differential function f(d) is produced. Then, by a stopping output generating means 5, the functions f(r) and f(d) are compared with each other, and when the f(r) is greater than the f(d), then stopping output Pl is applied to a differential relay 6. Besides, an accident detecting function computing means 3 is set, and the data Dj are used, and an accident detecting function f(f) is produced. When accident detecting signal Sf is generated, then into the means 5, the stopping output Pl is stored during a specified period, and the stopping output Pl is controlled not to be generated with data before the detection of an accident.
展开▼
