Abstract :
IT IS well known that when any portion of an electrical circuit is either opened or closed a transient condition will usually exist for some period, depending on the damping, before the circuit assumes its new steady state. In power circuits, such switching operations are the application and removal of faults or loads and the connecting or separating of various parts of a system. The transient conditions resulting from these switching operations give rise in some cases to overvoltages, which can be calculated by straightforward and more or less well-known methods, if the transient circuit parameters are known. However, in some instances voltages much higher than those predicted by such calculations have been obtained, and various explanations1–9 have been offered for these occurrences.
