VAMP 59 - Protection Stages; Differential Protection

Technical description
9 Technical data
9.3 Protection stages
VM59.EN001
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197
9.3. Protection stages
9.3.1. Differential protection
Line differential protection LdI> (87L)
Setting range
20 - 50 % I
N
(step 1%)
Bias current for start of slope 1
0.50 - 2.00 x I
N
(step 0.01)
Slope 1
50 - 200 % (step 1%)
Second harmonic blocking
Fifth harmonic blocking
5-30 % I
N
(step 1%)
20-50 % I
N
(step 1%)
Reset time
< 95 ms
Reset ratio
0.95
Inaccuracy:
- 2
nd
harmonic blocking
- 5
th
harmonic blocking
n/a
n/a
- Starting
±5% of set value or 0.05 x I
N
when currents are
> 200 mA
- Operating time (3.5 x I
SET
)
typically 35 ms
NOTE! The amplitude of second harmonic content has to be at least 2% of the
nominal of CT. If the nominal current is 5 A, the 100 Hz component needs
to exceed 100 mA.
Differential overcurrent stage Ldl>> (87L)
Setting range
2.0 - 20.0 x I
N
(step 0.1)
Second harmonic blocking
Fifth harmonic blocking
5-30 % I
N
(step 1%)
20-50 % I
N
(step 1%)
Inaccuracy:
- 2
nd
harmonic blocking
- 5
th
harmonic blocking
n/a
n/a
- Starting
±5% of set value
- Operating time (3.5 x I
SET
)
typically 35 ms
Transformer settings (scaling menu)
Connection group
None (no transformer)
Yy0, Yy6, Yd1, Yd5, Yd7, Yd11, Dy1, Dy5, Dy7,
Dy11, Dd0 and Dd6
Transformer side
HV (relay located on high voltage side)
LV (relay located on low voltage side)
Transformer grounding:
- I0 compensation (available 2012)
- I‟0 compensation (available 2012)
enabled or disabled depending whether
starpoint is grounded or not