is, autoreclose shots are allowed. If none of the trials is successful and the faultpersists, definite final tripping follows.The autoreclose function can be used with every circuit breaker that has the ability fora reclosing sequence. In DARREC autoreclose function the implementing method ofautoreclose sequences is patented by ABBTable 663:Important definitions related to auto-reclosingautoreclose shot an operation where after a preset time the breaker is closed from the breakertripping caused by protectionautoreclosesequencea predefined method to do reclose attempts (shots) to restore the power systemSOTF If the protection detects a fault immediately after an open circuit breaker has beenclosed, it indicates that the fault was already there. It can be, for example, aforgotten earthing after maintenance work. Such closing of the circuit breaker isknown as switch on to fault. Autoreclosing in such conditions is prohibited.final trip Occurs in case of a permanent fault, when the circuit breaker is opened for the lasttime after all programmed autoreclose operations. Since no auto-reclosing follows,the circuit breaker remains open. This is called final trip or definite trip.9.4.6.1 Shot initiationA070869 V1 ENFigure 339: Example of an autoreclosing program with a reclose scheme matrix1MRS758755 A Section 9Control functionsREC615 and RER615 649Technical Manual
