ABB REG650 Technical Manual page 248

Section 8
Voltage protection
242
delay in s
1800
under -
inverse delay law
excitation
overexcitation
0
M=V/Hz>
V/Hz>
IEC09000114 V1 EN
Figure 122: Restrictions imposed on inverse delays by
A definite maximum time of 1800 seconds can be used to limit the operate time at
low degrees of overexcitation. Inverse delays longer than 1800 seconds will not be
allowed. In case the inverse delay is longer than 1800 seconds, OEXPVPH trips.
A definite minimum time, tMin, can be used to limit the operate time at high
degrees of overexcitation. In case the inverse delay is shorter than tMin,
OEXPVPH function trips after tMin seconds. The inverse delay law is not valid for
values exceeding Mmax. The delay will be tMin, irrespective of the overexcitation
level, when values exceed Mmax (that is, M>V/Hz>).
tMin
M - V/Hz>
Overexcitation M-V/Hz>
max
M
Excitation M
max
E (only if f = fr = const)
E
max
IEC09000114-1-en.vsd
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Technical Manual