ABB ret650, Technical Manual

Page: 233 / 670

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 99: 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 99 .
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 504 135-UEN A
Section 9
Voltage protection
227
Technical manual