| 摘要 |
FIELD: electricity.SUBSTANCE: device contains: power direction monitoring unit, start-up unit of minimum frequency, resistance relay, the first logic unit, the first timer, the first minimum voltage monitoring unit, the second logic unit, the second timer, the third logic unit, the first actuating unit, the second minimum voltage monitoring unit, the third timer, and the second actuating unit. The first timer is output of minimum frequency protection with monitoring of power direction. The second timer is output of the first stage of minimum voltage protection with monitoring of power direction. The third timer is output of the first stage of minimum voltage protection. The first actuating unit cuts off input of busbar section that lost power supply and kills field of synchronous motors at the busbar section that lost power supply. The second actuating unit cuts off electric motors.EFFECT: improving stability of process systems owing to enhancing protection action and reducing the downtime of process units.2 dwg |
