EQUATION1310 V1 EN-US (Equation 242)
where:
X1
Zm
is the reactive reach for the zone to be covered by FRPSPDIS (21), and the constant
1.44 is a safety margin
X0
Zm
is the zero-sequence reactive reach for the zone to be covered by FRPSPDIS (21)
The reactive reach in reverse direction is automatically set to the same reach as for
forward direction. No additional setting is required.
Fault resistance reach
GUID-CB13A35F-0BF8-4CFA-9311-EADE194C1D85 v1
The resistive reach must cover RFPG for the overreaching zone to be covered, mostly
zone 2. Consider the longest overreaching zone if correct fault selection is important in
the application. Equation
243 and 244 gives the minimum recommended resistive
reach.
A) 60 degrees
ANSIEQUATION2223 V1 EN-US (Equation 243)
B) 90 degrees
( )
1
2 1 0
3
Zm Zm ZmRFFwPG R PG R PG RFPG> × × + +
ANSIEQUATION2224 V1 EN-US (Equation 244)
The security margin has to be increased in the case where φloop<60° to avoid that
FRPSPDIS (21) characteristic cuts of
f some part of the zone measurement
characteristic.
RFFwPP and RFFRvPP must be set in a way that the loop characteristic angle can be
60 degrees (or alternatively the same or lower compared to the measuring zone that
must be covered). If the characteristic angle for IEDs in the 500 series of 90 degrees is
desired, RFFwPP and RFFRvPP must be set to minimum setting values.
8.10.3.2 Phase-to-ground fault in reverse direction
M13142-151 v4
Reactive reach
M13142-153 v2
The reactive reach in reverse direction is the same as for forward so no additional
setting is required.
Section 8 1MRK 504 163-UUS A
Impedance protection
354 Transformer protection RET670 2.2 ANSI
Application manual
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