JPH0443343U - - Google Patents

Description

[Brief explanation of the drawing]

Fig. 1 is a schematic connection diagram of a power distribution system monitoring system according to an embodiment of this invention, Fig. 2 is a block diagram schematically showing the configuration of a pre-alarm relay in the embodiment of Fig. 1, and Fig. 3 is a FIG. 1 is a block diagram schematically showing the configuration of the alarm relay in the embodiment, and FIG. 4 is a schematic connection diagram of a conventional power distribution system. In the figure, 6a, 6b, 6c are circuit breakers, 7a, 7b, 7c, 7bR, 7bS, 7bT are current transformers, 8a, 8b, 8c are pre-alarm relays, and 9 is an alarm relay. In each figure, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Scope of utility model registration request] A current transformer connected in series to a circuit breaker installed in a power distribution system, which is connected to the output of this current transformer and whose circuit current exceeds a predetermined value but is less than the rated current of the circuit breaker. A power distribution system comprising a pre-alarm relay that operates in response to a corresponding current transformer output current, and an alarm relay that operates in response to an output signal of the pre-alarm relay and foretells the operation of the circuit or disconnector. Grid monitoring system.