Reactive reach
M13142-9 v4
The reactive reach in forward direction must as minimum be set to cover the measuring
zone used in the T
eleprotection schemes, mostly zone 2. Equation
251 and
equation 252 gives the minimum recommended reactive reach.
EQUATION1309 V1 EN-US (Equation 251)
EQUATION1310 V1 EN-US (Equation 252)
where:
X1
Zm
is the reactive reach for the zone to be covered by FDPSPDIS (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 FDPSPDIS (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
M13142-103 v5
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
253 gives the minimum recommended resistive reach.
min
1.1
zm
RFltFwdPG RFPG³ ×
EQUATION1724 V2 EN-US (Equation 253)
where:
RFPG
Zm
is the setting
RFPG
for the longest overreaching zone to be covered by FDPSPDIS (21).
The security margin has to be increased to at least 1.2 in the case where φloop<60° to
avoid that FDPSPDIS
(21) characteristic shall cut of
f some part of the zone
measurement characteristic.
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.
1MRK 504 163-UUS A Section 8
Impedance protection
Transformer protection RET670 2.2 ANSI 363
Application manual
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