Advanced Modelling of Inverter-Based Generators for Short-Circuit Current Calculations Based on IEC 60909-0:2016

Abstract

The bulk power system has undergone major changes since the beginning of the millennium due to the facilitated market access of renewable energy sources in many countries. These energy sources are often inverter-based and have a different network behaviour than the former predominant synchronous generators connected directly to the transmission system. The proper modelling of current sources in the superposition method is investigated and a simple short-circuit current calculation method is derived. The advanced method is applicable to the standard IEC 60909 and enables the consideration of dynamic reactive power support of inverter-based generators. A correction factor is introduced to compensate the disregard of pre-fault states in short-circuit current calculations according to the mentioned standard. By applying the method to a short-circuit study in a distribution grid, the advantage of the introduced method compared to the standard is confirmed.