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overcurrent elements DEF1I and DEF2I are enabled for DEF1 and DEF2 protection respectively,
and trip signal DEF1 TRIP and DEF2 TRIP are given.
The forward operate zone (DEF1F and DEF2F) or reverse operate zone (DEF1R and DEF2R) is
selectable by the scheme switches [DEF1-DIR] and [DEF2-DIR].
ICD is the inrush current detector ICD, which detects second harmonic inrush current during
transformer energisation, and can block the DEF1 and DEF2 protection by the scheme switches
[DEF1-2F] and [DEF2-2F] respectively. See Section 2.1.7.
The DEF1 and DEF2 protection can be disabled by the scheme switches [DEF1EN] and
[DEF2EN] or PLC logic signals DEF1 BLOCK and DEF2 BLOCK.
Figure 2.1.41 and Figure 2.1.42 show the scheme logic of the definite time earth fault protection
DEF3 and the DEF4. DEF3 and DEF4 give trip and alarm signals DEF3 TRIP and DEF4 ALARM
through delayed pick-up timers TDEF3 and TDEF4.
The forward operate zone (DEF3F and DEF4F) or reverse operate zone (DEF3R and DEF4R) is
selectable by the scheme switches [DEF3-DIR] and [DEF4-DIR].
The DEF3 and DEF4 protection can be disabled by the scheme switches [DEF3EN] and
[DEF4EN] or PLC logic signals DEF3 BLOCK and DEF4 BLOCK.
The DEF3 and DEF4 can also be blocked by the ICD.
132, 1824
DEF1F
&
148, 1840
DEF1R
&
"FWD"
[DEF1-DIR]
"REV"
+
[DEF1-2F]
+
&
"BLK"
ICD
[DEF1EN]
+
"ON"
1
1548
DEF1 BLOCK
Figure 2.1.39
133, 1825
DEF2F
&
149, 1841
DEF2R
&
"FWD"
[DEF2-DIR]
"REV"
+
[DEF2-2F]
+
&
"BLK"
ICD
[DEF2EN]
+
"ON"
1
DEF2 BLOCK
1549
Figure 2.1.40
84, 1776
DEF1I
≥1
[MDEF1]
+
"IEC"
"IEEE"
"US"
"CON"
"DT"
Directional Earth Fault Protection DEF1
85, 1777
DEF2I
≥1
[MDEF2]
+
"IEC"
"IEEE"
"US"
"CON"
"DT"
Directional Earth Fault Protection DEF2
⎯
⎯
45
6 F 2 S 0 8 4 2
421
≥1
&
1
TDEF
0
t
&
0.00 - 300.00s
422
≥1
&
TDEF2
0
t
&
0.00 - 300.00s
DEF1 TRIP
DEF2 TRIP
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