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
7.3.3.6

Setting of reach in resistive direction

Set the resistive reach
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 151.
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 zone 1 reach in resistive direction for phase-to-phase loop measurement in the phase
domain to:
RFPP ≤ ⋅ 6 1
IECEQUATION2306 V2 EN-US
7.3.3.7

Load impedance limitation, without load encroachment function

The following instructions are valid when Phase selection with load encroachment,
quadrilateral characteristic function FDPSPDIS is not used. The setting of the load resistance
RLdFw and RLdRv in FDPSPDIS must in this case be set to max value (3000). If FDPSPDISis 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 reach for any zone to
214
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
R1 independently for each zone.
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
1MRK 504 152-UEN B
(Equation 149)
(Equation 150)
SEMOD55087-84 v7
RFPP and for the phase-
(Equation 151)
(Equation 152)
(Equation 153)
(Equation 154)
SEMOD55087-97 v9
Application manual