Applying IEC 60909, short-circuit current calculations

Abstract

Rather than the short-circuit current that would occur in a specific instance, IEC 60909 derives the maximum and minimum prospective short-circuit currents in a system for each specific location and time. This is reported using a series of parameters which relate to the rated short-circuit current of equipment and the tests required on equipment to prove that rating. The influence of arc voltage on short-circuit currents is then discussed.