A comparison of static and dynamic short circuit analysis procedures

The authors examine the differences between static and dynamic short-circuit analyses by comparing the results of each for a specific industrial power system. The static method used is that of ANSI C37.XX, which essentially calculates short-circuit duties of static points of time. The dynamic method, which is data-intensive, calculates the value of short-circuit currents for any time from fault incidence. All system time constants are considered for each fault point, and the effects of prefault voltages, derived from load from studies, can also be considered. This algorithm is an order of magnitude more complex that the static one. It is found that static method is sufficiently accurate for the selection and specification of switchgear based on maximum available short-circuit duties.