Instruction manual
–
AQ G3x7 Generator protection IED
87 (211
)
3.2.14
R
ESIDUAL OVER VOLTAGE
U0>,
U0>>
(59N)
The residual definite time overvoltage protection function operates according to definite time
characteristics, using the RMS values of the fundamental Fourier component of the zero
sequence voltage (UN=3Uo).
Figure 3-51: The principal structure of the residual overvoltage function.
The general start signal is set active if the measured residual voltage is above the level
defined by pick-up setting value. The function generates a trip command after the set
definite time delay has elapsed.
Table 3-33: Setting parameters of the residual overvoltage function
Parameter
Setting value, range
and step
Description
Operation
Off
On
Operating mode selection for the function. Operation can be
either enabled “On” or disabled “Off”. Default setting is “On”.
Start voltage 2
…
60 % by step of 1
%
Voltage pick-up setting. Default setting 30 %.
Start signal
only
Activated
Deactivated
Selecti
on if the function issues either “Start” signal alone or
both “Start” and after set time delay “Trip” signal.
Default is
that both signals are generated (=deactivated).
Reset ratio
1…10% by step of
1%
Residual voltage protection reset ratio, default setting is 5%
Time delay
0…60000 ms by step
of 1 ms.
Operating time delay setting for the “Trip” signal from the
“Start” signal.
Default setting is 100 ms.
