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Definite time reset
A definite time reset characteristic is applied to the ZOV1 element when the inverse time delay is
used. Its operation is identical to that for the phase overvoltage protection.
Scheme Logic
Figure 2.2.12 shows the scheme logic of the zero sequence overvoltage protection. Two negative
sequence overvoltage elements ZOV1 and ZOV2 with independent thresholds output trip signals
ZOV1 TRIP and ZOV2 TRIP through delayed pick-up timers TZOV1 and TZOV2.
The tripping can be disabled by the scheme switches [ZOV1EN] and [ZOV2EN] or PLC logic
signals ZOV1 BLOCK and ZOV2 BLOCK.
228, 1920
ZOV1D
224, 1936
ZOV1I
"DT"
[ZOV1EN]
+
"IDMT"
1
1592
ZOV1 BLOCK
229, 1921
ZOV2
[ZOV2EN]
+
"ON"
1
1593
ZOV2 BLOCK
Figure 2.2.12
Setting
The table below shows the setting elements necessary for the zero sequence overvoltage
protection and their setting ranges.
Element
Range
ZOV1
5.0 - 130.0 V
ZOV2
5.0 - 130.0 V
TZOV1P
0.05 – 100.00
TZOV1D
0.00 – 300.00 s
TZOV1R
0.0 – 300.0 s
TZOV2
0.00 – 300.00 s
[ZOV1EN]
Off / DT/IDMT
[ZOV2EN]
Off / On
&
&
0.00 - 300.00s
&
&
≥1
678
&
&
0.00 - 300.00s
Zero Sequence Overvoltage Protection
Step
Default
Remarks
0.1V
20.0 V
ZOV1 threshold setting (V
0.1V
40.0 V
ZOV2 threshold setting (V
0.01
1.00
ZOV1-I time multiplier setting. Required if
[ZOV1EN]=IDMT.
0.01 s
1.00 s
ZOV1-D definite time setting. Required if [ZOV1EN]=DT.
0.1 s
0.0 s
ZOV1-I definite time delayed reset.
0.01 s
1.00 s
ZOV2 definite time setting
DT
ZOV1 Enable
Off
ZOV2 Enable
⎯
⎯
84
TZOV1
0
t
≥ 1
677
ZOV1 OP
TZOV2
t
0
) for tripping.
0
) for alarming.
0
6 F 2 S 0 8 4 2
474
ZOV1 TRIP
475
ZOV2 ALARM
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