FIELD: electricity.
SUBSTANCE: from the moment of occurrence of SC current surge on transformer buses of the main power source, there started is the first time reckoning equal to delay time of protection actuation of isolating switch of those buses; besides, moment of disappearance of SC current is controlled, and if at the end moment of the reckoned time the SC current disappears, a conclusion is made on trip of the isolating switch of the transformer buses of the main power source; from the moment of disappearance of SC current the second time reckoning is started, which is equal to delay time of switch-on of the standby switch of the main power source line; besides, in the standby power source line there controlled is occurrence of surge of operating current or SC current, and if at the end moment of the second time reckoning an operating current surge appears, with the value determined with the load of the line connected the standby power source and SC current does not appears, a conclusion is made on trip of the main switch and switch-on of the standby switch of the ring network line.
EFFECT: enlarging functional capabilities.
2 dwg
