Selection of Circuit Breaker Rating for Symmetrical Fault Analysis on Transmission Lines

Fault studies play a significant role in the power system analysis for stable and economical operations of a power system. Faults on power system are broadly divided into symmetrical and unsymmetrical faults. The paper describes the short circuit analysis for three phase symmetrical fault for finding the short circuit rating of circuit breaker. Circuit breakers serve as interrupting devices which interrupt the operating and short circuit currents. MATLAB based programs were written for load flow studies to determine prefault conditions and three phase short circuit studies. In this paper short circuit studies done on the IEEE 14 bus system which gives us maximum fault current and fault MVA rating which help in settings of relay.