POWER SUPPLY LOSS PROTECTION DEVICE Russian patent published in 2012 - IPC H02J9/06 

FIELD: electricity.

SUBSTANCE: device is composed of the following components: a unit of power direction control, a start-up unit of minimum frequency, the first, second and third logical AND units, the first, second and third timers, the first, second and third minimum voltage control units, a logical OR unit, the first and second actuating units. The first timer is an output of minimum frequency protection with control of power direction. The second logical OR unit and the second timer are an output of the first step of minimum voltage protection with control of power direction. The third timer is an output of the second step of minimum voltage protection. The first actuating unit acts at disconnection of a lead in a section of buses that lost power, and at suppression of a field of synchronous electric motors on a section of buses that lost power. The second actuating unit acts at disconnection of electric motors. The proposed device is designed for installation in cells of switchgears of transformer substations supplying to large synchronous electric motors.

EFFECT: higher resistance of process systems as a result of faster protection action and reduced idle time of process units.

2 dwg