From: Estimating zero-sequence impedance of three-terminal transmission line and Thevenin impedance using relay measurement data
Approach
Zero-sequence line impedance (Ω)
Magnitude error (%)
Phase angle error (degrees)
Actual
Estimated
Approach 1
15.08+j31.44
15.13+j31.33
0.22
0.15
Approach 2
15.12+j31.38
0.10