METHOD TO RECOGNISE REASON FOR AUTOMATIC CIRCUIT BREAKER OPENING AND DEVICE FOR ITS REALISATION Russian patent published in 2013 - IPC H02H3/08 

FIELD: electricity.

SUBSTANCE: in a power feeder an electric parameter is controlled, and if an automatic circuit breaker opens, an emergency condition signal is generated, opening of automatic circuit breaker contacts is determined by absence of voltage at its output, the monitored parameter is voltage arising on an element of a thermal protection of the automatic circuit breaker as it opens from a short circuit in a network, this voltage is compared with two threshold values of different polarity, if the value of the monitored parameter equals to or exceeds the threshold value of any polarity, a trigger is changed into a single condition, if there are open contacts of the automatic circuit breaker, an emergency condition signal is generated, indication of trigger conditions is carried out, the reason for opening is detected on the basis of the trigger condition, in case of its zero condition it is recognised that the reason for opening of the automatic circuit breaker is "overload", in case of its single condition it is recognised that the reason for opening of the automatic circuit breaker is "short circuit".

EFFECT: simplified technical realisation and expansion of method and device information value.

2 cl, 1 dwg