ABB COM600 series User's & Technical Manual page 16

16
COM600 series 5.1
Substation Analytics Technical Manual
fault loops. SCEFRFLO employs independent algorithms for each fault type to achieve
optimal performance.
The inherent result from the fault distance calculation is the ohmic fault loop impedance
value.
Figure 4.3-3 (Equation 2)
The value can be utilized as such or it can be further processed in system level fault
localization applications.
Depending on the fault loop, the composition of the terms RFLOOP and XFLOOP is
different.
Fault loops "AG Fault" or "BG Fault" or "CG Fault"
Fault loops "AG Fault", "BG Fault" or "CG Fault" are used for single-phase-to-earthfaults.
When the individual earth faults are located at different feeders, they are also applied in
the case of a phase-to-phase-to-earth-fault. In this case, the phase-toearth loop (either
"AG Fault" or "BG Fault" or "CG Fault") corresponding to the faulty phase at the pro-
tected feeder, is used for calculation. Figure 4.3-8 shows the measured impedances.
Fault loops "AG Fault", "BG Fault" or "CG Fault" measure the impedance which, at the
same time, are the outputs of SCEFRFLO.
Figure 4.3-4 (Equation 3)
Figure 4.3-5 (Equation 4)
Figure 4.3-6 (Equation 5)
1MRS758734
equation_2.png
equation_3.png
equation_4.png
equation_5.png