ABB RET670 Applications Manual page 308

Section 3
IED application
302
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:
2
æ
X
m0
×
ç ------------------------- -
R = R 1 +
0E 0
2
è
R + X
0 0
EQUATION561 V1 EN
2
æ
X
m0
×
------------------------- -
X = X ç 1 –
0E 0
2
è
R + X
0 0
EQUATION562 V1 EN
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.
1
( ) RFPE
×
-- - 2 R1PE
R = + R0PE
3
EQUATION567 V1 EN
é
j
×
2 X1PE + X0
ê
=
loop arctan
×
ê
2 R1PE + R0
ë
EQUATION1457 V1 EN
Setting of the resistive reach for the underreaching zone1 should follow the condition:
£ ×
RFPE 4.5 X 1
EQUATION569 V2 EN
ö
÷
2
ø
ö
÷
2
ø
+
ù
ú
ú
û
1MRK504116-UUS C
(Equation 225)
(Equation 226)
(Equation 227)
(Equation 228)
(Equation 229)
Application manual