Selectivity, also known as circuit breaker discrimination, is the coordination of
overcurrent protection devices so that a
fault in the installation is cleared by the protection device located immediately upstream of the fault. The purpose of selectivity is to minimize the impact of a failure on the network. Faults in an installation are, for example, overload and
short circuit
A short circuit (sometimes abbreviated to short or s/c) is an electrical circuit that allows a current to travel along an unintended path with no or very low electrical impedance. This results in an excessive current flowing through the circuit ...
.
There are four ways in which selectivity is achieved:
[{{cite web, url=https://eduscol.education.fr/sti/sites/eduscol.education.fr.sti/files/ressources/techniques/3363/3363-ect201.pdf, title=Discrimination with LV power circuit-breakers, author=Jean-Pierre Nereau, date=April 2001, publisher=]Schneider Electric
Schneider Electric SE is a French multinational company that specializes in digital automation and energy management. It addresses homes, buildings, data centers, infrastructure and industries, by combining energy technologies, real-time automation ...
, page=6, language=en, access-date=18 September 2021, url-status=live, archive-url=https://web.archive.org/web/20210917145624/https://eduscol.education.fr/sti/sites/eduscol.education.fr.sti/files/ressources/techniques/3363/3363-ect201.pdf, archive-date=17 September 2021
* Current selectivity: different
breaking capacities
* Time selectivity: time delay before tripping of a breaker
* Energy based selectivity: analysis of the current waves
* Zone selective interlocking: communication between the breakers, forwarding a time delay instruction
References
Electrical engineering
Electrical safety