VAMP 257 - Directional Current Protection (67)

To Next Page

To Previous Page

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

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

)

*) 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