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Instruction manual
–
AQ G3x7 Generator protection IED
91 (211
)
The function block of third harmonic undervoltage protection function is shown in figure
below. All binary input and output status signals applicable in the AQtivate 300 software are
explained below.
Figure 3-55: The function block of the impedance protection function with offset
characteristic
Table 3-34: Setting parameters of the harmonic undervoltage protection 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
Selection 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).
Time delay
0…60000 ms by step
of 1 ms.
Operating time delay settin
g for the “Trip” signal from the
“Start” signal.
Default setting is 100 ms.
3.2.16
O
VER FREQUENCY F
>,
F
>>
(81O)
The deviation of the frequency from the rated system frequency indicates unbalance
between the generated power and the load demand. If the available generation is large
compared to the consumption by the load connected to the power system, then the system
frequency is above the rated value.