Worst case studies of short-circuit making-currents

Short-circuit peak currents exceeding the testing value according IEC standards can be caused by the nonsimultaneous closing of the poles of a circuit breaker during switching or reclosing while the network is in short-circuit state and by the successive involvement of the three phases during the development of a three-phase fault as well. The authors treat the theoretical relations of the short-circuit currents during nonsimultaneous pole closing or fault development in a network where either the source or the fault is ungrounded. The authors also consider the resulting short-circuit current when a short-circuit happens during the energisation of a capacitor bank