9.3 Protection stages
9 Technical data
Technical description
218
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VM50.EN004
9.3.
Protection stages
NOTE! Please see chapter 2.4.2 for explanation of I
mode
.
9.3.1.
Overcurrent protection
Overcurrent stage I> (50/51)
Pick-up current
0.10 – 5.00 x I
mode
Definite time function:
DT
- Operating time
0.08
**)
– 300.00 s (step 0.02 s)
IDMT function:
- Delay curve family
(DT), IEC, IEEE, RI Prg
- Curve type
EI, VI, NI, LTI, MI…depends on the family *)
- Time multiplier k
0.05
20.0, except
0.50
20.0 for RXIDG, IEEE and IEEE2
Start time
Typically 60 ms
Reset time
<95 ms
Reset ratio
0.97
Inaccuracy:
- Starting
±2% of the set value
- Operating time at definite time function
±1% or ±30 ms
- Operating time at IDMT function
±5% or at least ±30 ms (I< 50 x I
mode
)
*) EI = Extremely Inverse, NI = Normal Inverse, VI = Very Inverse, LTI = Long Time Inverse
MI= Moderately Inverse
**) This is the instantaneous time i.e. the minimum total operational time including the fault
detection time and operation time of the trip contacts.
Overcurrent stages I>>, I>>> and I>>>> (50/51)
Pick-up current
0.10 – 20.00 x I
n
(I>>)
0.10 – 40.00 x I
n
(I>>>)
Definite time function:
0.04
**)
– 300.00 s (step 0.01 s)
- Operating time
Start time
Typically 60 ms
Reset time
<95 ms
Reset ratio
0.97
Inaccuracy:
- Starting
±2% of the set value
- Operation time
±1% or ±25 ms
**) This is the instantaneous time i.e. the minimum total operational time including the fault
detection time and operation time of the trip contacts.