8.2 Voltage-dependent (restraint) overcurrent
This protection is used when the generator must be tripped due to a fault situation that creates a reduced
generator voltage, e.g. a voltage collapse. During the voltage collapse, the generator can only produce part of
its usual rating. A short-circuit current during a voltage collapse can even be lower than the nominal current
rating.
The protection will be activated based on the overcurrent setpoint as a function of the measured voltage on
the generator voltage terminals.
The result can be expressed as a curve function where the voltage setpoints are fixed values and the current
setpoints can be adjusted (menu 1100). This means that if the voltage drops, the overcurrent setpoint will al-
so drop.
100
110
120
130
140
150
160
170
180
190
200
50
60
70
80
90
100
% Nominal Voltage
%
N
o
m
in
a
l
C
u
rr
e
n
t
The voltage values for the six points on the curve are fixed; the current values can be adjusted
in the range 50-200%.
Voltage and current % values refer to the nominal settings.
Timer value can be adjusted in the range 0.1- 60.0 sec.
CGC 400 DRH 4189340786 UK
Protections
DEIF A/S
Page 95 of 96