ABB REG650 - Page 287

0 M
max
- V/Hz>
M
max
tMin
V/Hz>
E
max
E (only if f = fr = const)
1800
inverse delay law
overexcitation
under -
excitation
delay in s
IEC09000114-1-en.vsd
Overexcitation M-V/Hz>
Excitation M
M=V/Hz>
IEC09000114 V1 EN
Figure 139: Restrictions imposed on inverse delays by
A definite maximum time of 1800 seconds is used to limit the operate time at low
degrees of overexcitation of V/Hz>. Inverse delays longer than 1800 seconds will not
be allowed. In case the inverse delay is longer than 1800 seconds, OEXPVPH trips
tMax, see figure
139.
A definite minimum time (tMin), can be used to limit the operate time at high degrees
of overexcitation for V/Hz>. In case the inverse delay is shorter than tMin, OEXPVPH
function trips after tMin seconds.
1MRK 502 048-UEN A Section 9
Voltage protection
281
Technical manual