VAMP 257 - Frequency Protection Stages (81 H;81 L); Second Harmonic Function (68); Rate of Change of Frequency (ROCOF) Protection (81 R)

VAMP 257 Feeder and motor manager
Technical description
VAMP Ltd
144
VAMP 24h support phone : +358 (0)20 753 3264
VM257.EN002
5.3.6. Frequency protection
Overfrequency and underfrequency protection stages f><
and f>><<
Frequency measuring range 46.0 - 70.0 Hz
Definite time function:
-operating time 0.10
**)
– 300.0 s (step 0.02 s)
Starting time 80 ms
Reset time 100 ms
Reset ratio (f> and f>>) 0.998
Reset ratio (f< and f<<) 1.002
Inaccuracy:
- starting ±20 mHz
- operating time ±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.
Underfrequency stages f< and f<<
Underfrequency measuring range 40.0 - 64.0 Hz
Definite time function:
-operating time 0.10
**)
- 300.0 s (step 0.02 s)
Undervoltage blocking 2 – 100 %
Starting time 80 ms
Reset time 100 ms
Reset ratio 1.002
Inaccuracy:
- starting ±20 mHz
- operating time ±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.
5.3.7. Second harmonic function
2. Harmonic stage / Inrush (68)
Settings:
- Setting range 2.Harmonic 10 – 100 %
- Operating time 0.05** – 300.00 s (step 0.01 s)
**) This is the instantaneous time i.e. the minimum total operational time including the fault
detection time and operation time of the trip contacts.
5.3.8. Rate of change of frequency df/dt protection
(81R)
ROCOF stage df/dt 81R
Pick-up setting df/dt 0.2 – 10.0 Hz/s (step 0.1 Hz/s)
Definite time delay (t> and t
Min
> are equal):
- operating time t> 0.14
**)
– 10.00 s (step 0.02 s)
Inverse time delay (t> is more than t
Min
>):
- minimum operating time t
Min
> 0.14
**)
– 10.00 s (step 0.02 s)
Starting time 140 ms
Reset time t>
Inaccuracy:
- starting ±0.1 Hz/s
- operating time(overshoot ≥ 0.2 Hz/s)
±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.