ABB RET670 - Page 308

Parallel line is out of service and grounded in both ends
Apply the same measures as in the case with a single set of setting parameters. This
means that an underreaching zone must not overreach the end of a protected circuit for
the single phase-to-ground faults. Set the values of the corresponding zone (zero-
sequence resistance and reactance) equal to:
R
0E
R
0
1
X
m0
2
R
0
2
X
0
2
+
--------------------------
+
è ø
ç ÷
æ ö
×=
EQUATION561 V1 EN (Equation 225)
X
0E
X
0
1
X
m0
2
R
0
2
X
0
2
+
--------------------------
–
è ø
ç ÷
æ ö
×=
EQUATION562 V1 EN (Equation 226)
Setting of reach in resistive direction
Set the resistive reach independently for each zone, for phase-to-ground loop (RIPE)
measurement.
Set separately the expected fault resistance for the phase-to-ground faults (RFPE) for
each zone. Set all remaining reach setting parameters independently of each other for
each distance zone.
The final reach in resistive direction for phase-to-ground fault loop measurement
automatically follows the values of the line-positive and zero-sequence resistance, and
at the end of the protected zone is equal to equation
227.
R
1
3
---
2 R1PE× R0PE+
( )
RFPE+=
EQUATION567 V1 EN
(Equation 227)
2 X1PE+X0
arctan
2 R1PE +R0
loop j
é ù
×
ê ú
=
×
ê ú
ë û
EQUATION1457 V1 EN (Equation 228)
Setting of the resistive reach for the underreaching zone1 should follow the condition:
4.5 1
RFPE X£ ×
EQUATION569 V2 EN
(Equation 229)
Section 3 1MRK504116-UUS C
IED application
302
Application manual