ABB COM600 series User's & Technical Manual page 20

20
COM600 series 5.1
Substation Analytics Technical Manual
Figure 4.3-13 (Equation 10)
Figure 4.3-14 (Equation 11)
Figure 4.3-15 Fault loop impedance for phase-to-phase fault impedance loops (either "AB Fault",
"BC Fault" or "CA Fault")
For the fault loops 12, 23, 31, the estimated fault resistance
is half the total fault resistance between the phases.
The fault distance calculation algorithm for the phase-to-phase fault impedance loops
(12, 23 or 31) is defined by using setting Load Com PP loops = "Disabled"/"Enabled"
setting and setting Simple mode PP loops = "Disabled"/"Enabled".
The load compensation can be enabled or disabled with the Load Com PP loops =
FALSE/TRUE setting. The load compensation should be disabled only if the ratio between
the fault current and load current is large or when the value of the fault distance estimate
for the short circuit fault is required for each shot of an autoreclosing cycle.
The fault distance calculation is the most accurate when the calculation is made with the
fault loop model. This model requires positive sequence impedances as initial data. If
the data is not accessible, the calculation can be made with a simple fault loop model
that does not need any impedance data. The simple fault loop model is enabled, with the
value Simple mode PP loops = TRUE. When the simple model is enabled, the conversion
of electrical fault distance into a physical distance is not done in the IED and the
fault_loop_impedance_phase-to-phase_fault_impedance_loops.png
1MRS758734
equation_10.png
equation_11.png