ABB COM600 series User's & Technical Manual page 31

1MRS758734 COM600 series 5.1
Substation Analytics Technical Manual
equation_18.png
Figure 4.3-28 (Equation 18)
R1 conductor AC Resistance [ /km]
the equivalent depth [m] of the earth return path Earth resistivity
r the equivalent radius [m] for conductor bundle radius[m] for signal conductor
axy distance [m] between phase x and y
Ph leakage Ris and Ph capacitive React settings
The Ph leakage Ris and Ph capacitive React settings are used for improving fault distance
estimation accuracy for earth faults. They are critical for an accurate fault location in
unearthed networks. In other types of networks they are less critical.
The Ph leakage Ris setting represents the leakage losses (resistive losses due to insulators
and so on) of the protected feeder in terms of resistance per phase. The Ph capacitive
React setting represents the total phase-to-earth capacitive reactance of the protected
feeder per phase. Based on experience, a proper estimate for Ph leakage Ris should be
about 20...40 × Ph capacitive React.
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