scope:

IEC TR 63401-4:2022 (E), which is a technical report, focuses on the fault behaviour of IBRs and performances of the existing relay protection in grids with large-scale integration of IBRs. This document includes: The IBR fault current requirements in present grid codes, including the requirements of active and reactive currents in positive- and negative-sequence systems during symmetrical and unsymmetrical faults. Fault current behaviour of IBRs, including the current components in transient and fundamental frequency in different IBR topology and control schemes. Adaptability of existing relay protection with the large-scale integration of IBRs, including the performances of distance protection, phase selector, directional relay and over-current protection.