METHOD FOR DISCONNECTING SHORT-CIRCUIT CURRENTS IN CIRCUITS OF THERMAL POWER STATION UNITS Russian patent published in 2001 - IPC

FIELD: electrical engineering; differential short-circuit protection of thermal-station power units. SUBSTANCE: protective circuit has series-connected generator, generator circuit breaker, transformer, and high-voltage circuit breaker. Generator is provided with differential protective gear connected to current transformers. Transformer has differential protective gear connected to current transformers. Power unit has differential protective gear connected to current transformers. Output of generator differential protective gear is connected to final element of high-voltage circuit breaker and to that of generator field suppressor. Output of transformer differential protective gear is connected to final element of generator circuit breaker and to high-voltage circuit breaker. Output of power-unit differential protective gear is connected to final element of high-voltage circuit breaker and to final element of generator field suppressor and also to final element of generator circuit breaker through OFF- control of high-voltage circuit breaker. Proposed circuit arrangement ensures high speed of response to short-circuit currents, reliable disconnection of generator winding on occurrence of short circuits, and places less stringent requirements to generator circuit breaker. EFFECT: reduced weight, size, and cost. 2 cl, 1 dwg