Maximum Earth Fault Loop Impedance Check
The software calculates the maximum loop impedance to check that the protective device functions within time limits in the event of an earth fault.
See Maximum Earth Fault Loop Impedance (max Zs) Calculation
Recommendation to resolve the error:
Revise the protective device, Z1 (impedance of the phase conductor), Z2 (impedance of the CPC). Also make sure the upstream circuits have been set correctly.