It means the protection is measuring three fault loops for phase-to-phase faults (L1-L2, L2-L3, L3-L1) and three phase-to-ground fault loops (L1-N, L-2N, L3-N). The combination of all six loops covers all 11 types of short-circuit faults that can occur in a solidly. What is the function of power system protection? For what purpose is IEEE device 52 is used? Why are seal-in and 52a contacts used in the dc control scheme? In a typical feeder OC protection scheme, what does the residual relay measure? Questions? 00000001 00000101 00001001 00100100 10010000 :. The protection and control devices in electrical equipment can be referred to by numbers, with appropriate suffix letters when necessary, according to the functions they perform. These numbers are based on a system that is adopted by a standard for automatic switchgear by Institute of Electrical. Combination of fast fault clearance with selective operation of protection element is the main objective for the protection of electrical power systems. loss of synchronism protection, loss of excitation protection, or impedance automatics like fault locator. Impedance relays measure and evaluate the magnitude and angle of impedance and therefore these relays are adjusted to the power line parameters. Also. Protective relays and devices have been developed over 100 years ago to provide “last line” of defense for the electrical systems.
