Setting Of Reach In Resistive Direction; Load Impedance Limitation, Without Load Encroachment Function - ABB RELION 670 Series Applications Manual

Section 7
Impedance protection
R =
0E
EQUATION561 V1 EN-US
X =
0E
EQUATION562 V1 EN-US
7.9.3.6

Setting of reach in resistive direction

Set the resistive independently for each zone.
Set separately the expected fault resistance for phase-to-phase faults
to-earth faults
parameters independently of each other.
The final reach in resistive direction for phase-to-earth 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 281.
1
(
=
R
3
IECEQUATION2303 V1 EN-US
j
=
loop
EQUATION2304 V1 EN-US
Setting of the resistive reach for the underreaching zone 1 should follow the condition to
minimize the risk for overreaching:
£
RFPE
IECEQUATION2305 V1 EN-US
The fault resistance for phase-to-phase faults is normally quite low, compared to the fault
resistance for phase-to-earth faults. To minimize the risk for overreaching, limit the setting of
the zone1 reach in resistive direction for phase-to-phase loop measurement in the phase
domain to:
RFPP ≤ ⋅ 6 1
IECEQUATION2306 V2 EN-US
7.9.3.7

Load impedance limitation, without load encroachment function

The following instructions are valid when Phase selection with load enchroachment,
quadrilateral characteristic function FRPSPDIS is not activated. To deactivate the function, the
setting of the load resistance
If FRPSPDIS is to be used for all or some of the measuring zones, the load limitation for those
zones according to this chapter can be omitted. Check the maximum permissible resistive
282
2
æ ö
X
m0
×
ç ------------------------- - ÷
R 1 +
0
2 2
è ø
R X
+
0 0
2
æ ö
X
m0
×
------------------------- -
X ç 1 – ÷
0
2 2
è ø
R + X
0 0
RFPE for each zone. For each distance zone, set all remaining reach setting
)
× + +
2 R1 R0 RFPE
é × + ù
2 X1 X0
arctan
ê ú
ë û
× +
2 R1 R0
×
4.5 X1
X
RLdFw and RLdRv in FRPSPDIS must be set to max value (3000).
1MRK 505 343-UEN B
(Equation 279)
(Equation 280)
GUID-3BFE80FD-8A51-4B71-8762-73DFA73AB28B v2
RFPP and for the phase-
(Equation 281)
(Equation 282)
(Equation 283)
(Equation 284)
GUID-A7CDE76A-D5B5-4641-9324-2E9A99071DF5 v1
Application manual