ABB Switzerland Ltd REG 316*4 1MRB520049-Uen / Rev. F
3-142
E. Setting instructions
Settings:
Overvoltage V-Setting
Delay Delay
Minimum frequency f-min
Over or undervoltage MaxMin
The instantaneous overvoltage function is a high-speed protec-
tion, which operates in a wide frequency range. It is intended
primarily for the following applications:
· where an overvoltage protection is required, which is largely
insensitive to frequency especially for f > f
N
.
The limited capacity of the v.t’s to transform low frequencies
must be taken into account for f < f
N
:
Input transformer units K01...K17 (REL 316*4) and K41...K47
(REC 316*4):
N
f
f
×
N
1.3U
Input transformer units K21...K24 (RET 316*4) and K61...K68
(REG 316*4):
N
f
f
×
N
2.25U
· where high-speed protection is required. The high speed is
achieved by measuring the instantaneous value of the volt-
age and since DC components and harmonics are not sup-
pressed, by eliminating the inertia of the digital input filter.
Compared with the normal voltage function, the instantaneous
function has a larger tolerance on the pick-up setting. It should
therefore only be used in the above two cases.
The measuring principle is the same as that of the peak value
current function and therefore reference should be made to that
Section for a description of the principle and the significance of
the minimum frequency setting f-min.
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