Patent ID: 6236548
Filing Date: 2001-05-22
Classification: H01H

Abstract:
A method of discriminating between an internal arc and a circuit-breaking arc established inside the enclosure of a circuit breaker in a bay of a medium or high voltage metal-clad substation, by means of measurements of the pressure of the dielectric gas inside the enclosure of said circuit breaker, in which the appearance of an internal arc is detected by a protection system which responds by transmitting a disengagement order to the circuit breaker to cause its contacts to separate, said separation causing a circuit-breaking arc to appear, the method comprising the following steps:continuously measuring the pressure of the dielectric gas inside the enclosure of the circuit breaker;recording said pressure measurements so that after the instant at which the disengagement order is transmitted, a first pressure value measured before said instant can be recovered; andcomparing said first pressure value with a second pressure value measured after said instant to identify that an internal arc is established in said circuit breaker enclosure if the second value is greater than the first value, or that the internal arc is not established in said circuit breaker enclosure if both pressure values are equal.