ABB REG670 - Page 194

X
R
ArgDir
ArgNegRes
ZPP
ZRevPP
UL1L2
ϕ
IL1L2
en06000469.eps
IEC06000469 V1 EN
Figure 69: Operation characteristic for reverse phase L1-to-L2 fault
Phase-to-earth fault
Mho
The measuring of earth faults uses earth-return compensation applied in a
conventional way. The compensation voltage is derived by considering the influence
from the earth-return path.
For an earth fault in phase L1, the compensation voltage Ucomp can be derived, as
shown in Figure
70.
Section 7 1MRK502052-UEN B
Impedance protection
188
Technical manual