8.3.4.7 Setting of reach in resistive direction
GUID-43EE13AF-BEBC-4A13-95B3-53C28B9164CB v3
Set the resistive reach R1 independently for each zone.
Set separately the expected fault resistance for phase-to-phase faults RFPP and for the
phase-to-ground faults RFPG for each zone. For each distance zone, set all remaining
reach setting parameters independently of each other
.
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
131.
( )
1
R 2 R1 R0 RFPG
3
= × + +
ANSIEQUATION2303 V1 EN-US (Equation 131)
2X1Zx X0Zx
arctan
2 R1Zx R0Zx
loop
EQUATION2304 V2 EN-US (Equation 132)
Setting of the resistive reach for the underreaching zone 1 should follow the condition
to minimize the risk for overreaching:
ANSIEQUATION2305 V1 EN-US (Equation 133)
The fault resistance for phase-to-phase faults is normally quite low, compared to the
fault resistance for phase-to-ground faults. T
o minimize the risk for overreaching, limit
the setting of the zone 1 reach in resistive direction for phase-to-phase loop
measurement to:
IECEQUATION2306 V3 EN-US (Equation 134)
Note that RLdFwd and RldRev are not only defining the load encroachment boundary.
They are used internally as reference points to improve the performance of the phase
selection. In addition, they define the impedance area where the phase selection
element gives indications, so do not set RLdFwd and RldRev to excessive values even
if the load encroachment functionality is not needed (that is, when the load is not
encroaching on the distance zones).
Always define the load encroachment boundary
according to the actual load or in consideration of how far the phase selection must
actually reach.
Section 8 1MRK 502 071-UUS A
Impedance protection
274 Generator protection REG670 2.2 ANSI and Injection equipment REX060, REX061, REX062
Application manual
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