Short-circuit study is the analysis of an electrical system which gives the magnitude of the current that will flow during an electrical hazard. Comparing these results with the equipment ratings is the primary step for ensuring that our electrical network is safely protected. Once the short-circuit currents are calculated, a protection coordination study will be performed to determine the optimum characteristics, ratings and settings of the protective devices.
The preliminary short-circuit/protection study should be carried when an electrical network is first designed. But, for various systems, this is mistakenly the last time it is done. This kind of studies should be performed on a regular interval of time like every four to five years in more static situations. As often as it is required whenever a change occurs due to power company energy changes or facility renovation and addition of new equipment, such as circuit breakers, motor controls, transformers and cables.