Short circuit analysis is primarily required to compute the following: 1 Three phase fault level at one or more nodes (busses) in the system. In turn, the 3o fault level is used to decide the short circuit current interruption capacity of circuit breakers. The issue will be discussed in more detail in section-5. 2 Evaluate fault currents for faults on transmission lines and the corresponding contribution from the adjacent busses. Such current pairs are used in the coordination of overcurrent relays. This application will be discussed in detail in section 7.