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
4.98+j10.42
4.99+j10.39
0.19
0.11
Approach 2
4.95+j10.46
0.20
0.22