ABB RELION REX640 Technical Manual page 1105

1MRS759142 C
REX640
Technical Manual
These impedance values can be used as such or they can be further processed in
system-level fault location applications, such as distribution management system
(DMS).
Fault loops "AG Fault", "BG Fault" and "CG Fault"
Fault loops "AG Fault", "BG Fault" and "CG Fault" are used for single-phase-to-earth
faults. When the earth faults are located at different feeders, they are also applied in
the case of two-phase-to-earth faults. In this case, the phase-to-earth loop ("AG
Fault", "BG Fault" or "CG Fault") corresponding to the faulty phase at the protected
feeder is used for calculation.
The following impedances are measured and stored in the recorded data of
SCEFRFLO.
Flt point resistance R
=
GUID-129AE961-A5F3-4E2E-BB63-A9F6099DD8D0 V1 EN
Flt loop resistance R
=
1
GUID-A2A3E535-0653-4682-9B0D-BF1CEF38F5E5 V1 EN
Flt loop reactance X
=
1
GUID-27951579-3052-4729-BCEF-618CA9EDA0B4 V1 EN
Flt phase reactance X
=
GUID-0E300AAB-19CE-4FDC-AFD9-CF9D7BFAE204 V1 EN
R Estimated positive-sequence resistance from the substation to the fault location
1
X Estimated positive-sequence reactance from the substation to the fault location
1
R Estimated zero-sequence resistance from the substation to the fault location
0
X Estimated zero-sequence reactance from the substation to the fault location
0
R Estimated earth return path resistance (= (R0 – R1)/3) from the substation to the
N
fault location
X Estimated earth return path reactance (= (X0 – X1)/3) from the substation to the
N
fault
R Estimated fault resistance at the fault location
fault
The recorded data Flt phase reactance provides the estimated positive-sequence
reactance from the substation to the fault location.
Protection related functions
Figure 596 shows the phase-to-earth fault loop model.
fault
R R
+ +
N fault
X
+
N
1
Section 5
(Equation 259)
(Equation 260)
(Equation 261)
(Equation 262)
1099