ABB RELION Series Technical Manual page 491

1MRS758755 A
REC615 and RER615
Technical Manual
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-earth
faults. When the individual earth faults are located at different feeders, they are also
applied in the case of two-phase-to-earth fault. In this case, the phase-to-earth loop
(either "AG Fault" or "BG Fault" or "CG Fault") corresponding to the faulty phase at
the protected feeder, is used for calculation.
loop model. The following impedances are measured and stored in the recorded data
of SCEFRFLO.
Flt point resistance R
=
GUID-2503378E-4AC5-4E9F-9D77-2E7C71592C37 V3 EN
Flt loop resistance R
=
1
GUID-4DF67AFC-67E4-4BCB-958E-CC9E4872E252 V3 EN
Flt loop reactance X
=
1
GUID-B4E21936-B993-4A8A-9C4A-7425F8AC4670 V3 EN
Flt phase reactance X
=
GUID-56EC16DD-7F6A-4DE5-935E-4302196DE21A V3 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 the earth return path resistance (= (R0 – R1)/3) from the substation to
N
the fault location
X Estimated is the earth return path reactance (= (X0 – X1)/3) from the substation to
N
the 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 250
fault
R R
+ +
N fault
X
+
N
1
Section 5
shows the phase-to-earth fault
(Equation 46)
(Equation 47)
(Equation 48)
(Equation 49)
485