Power System and Faults

. A Power System consists of various electrical components like Generator, transformers, transmission    lines, isolators, circuit breakers, bus bars, cables, relays, instrument transformers, distribution feeders,  and various types of loads. 

. Faults may occur in any part of power system as a short circuit and earth fault. Fault may be Single Line  to Ground, Double Line to Ground, Line to Line, three phase short circuit etc. This results in flow of  heavy fault current through the system.
 

. Fault level also depends on the fault impedance which depends on the location of fault referred from the  source side.