VAMP Ltd
Feeder and motor manager
Technical description
VAMP 257
VM257.EN002
VAMP 24h support phone : +358 (0)20 753 3264
141
5.3.2.
Directional current protection
Directional overcurrent stages I
dir
> and I
dir
>> (67)
Pick-up current
0.10 - 4.00 x I
mode
Mode Directional/non-directional
Minimum voltage for the direction solving
- Setting range
1%..20% x VT
0
Secondary
Base angle setting range
-180
°
to + 179
°
Operation angle
±88
°
Definite time function:
DT
- Operating time
0.06
**)
– 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
Start time
60 ms
Reset time
80 ms
Reset ratio
0.95
Inaccuracy:
- Starting (rated value IN= 1 – 5A)
±3% of the set value or ±0.5% of the rated
value
- Angle
±2
°
- Operate time at definite time function
±1% or ±30 ms
- Operate time at IDMT function
±5% or at least ±30 ms (I< 50 x I
n
)
*) 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.
Limitations:
The maximum measured secondary current is 250 A. This limits the scope of
inverse delays if the setting is more than 12.5 A
.
Directional overcurrent stages I
dir
>>> and I
dir
>>>> (67)
Pick-up current
0.10 – 20.0 x I
mode
Mode Directional/non-directional
Minimum voltage for the direction solving
0.01 pu
Base angle setting range
-180
°
to + 179
°
Operation angle
±88
°
Definite time function:
DT
- Operating time
0.06
**)
– 300.00 s (step 0.02 s)
Start time
60 ms
Reset time
80 ms
Reset ratio
0.95
Inaccuracy:
- Starting (rated value IN= 1 .. 5A)
±3% of the set value or ±0.5% of the rated
value
- Angle
±2
°
- Operate time at definite time function
±1% or ±30 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.