Abstract:
Basic idea of protection is to ensure the availability of electrical energy without interruption to every load connected to the system. Protective relays and relaying systems detect abnormal conditions like faults in electric circuits and operate automatic switchgear to isolate faulty equipment from the system as quickly as possible, to limit the damage at the fault location and to present the effects of the fault spreading into the system. Thus the main function of a protective relay is to isolate a faulty section as quickly as possible with the least interruption to service by controlling the circuit breaker, when abnormal condition develop. So, the relay may be designed to detect and to measure abnormal conditions and close the contacts in the tripping circuit....
