Instruction manual
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AQ G3x7 Generator protection IED
71 (211
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The function can be disabled by parameter setting, and by an input signal programmed by the
user.
The trip command is generated after the set defined time delay.
Table 3-23: Setting parameters of the current unbalance function
Parameter
Setting value, range
and step
Description
Operation
On
Off
Selection for the function enabled or disabled. Default setting
is “On” which means function is enabled.
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).
Start current
10…90 % by step of
1 %
Pick up setting of the current unbalance. Setting is the
maximum allowed difference in between of the min and max
phase currents. Default setting is 50 %.
Time delay
0…60000 ms by step
of 100 ms
Operating time delay setting for the “Trip” signal from the
“Start” signal.
Default setting is 1000 ms.
3.2.10
N
EGATIVE SEQUENCE OVERCURRENT
(46)
The negative sequence overcurrent protection function (TOC46) block operates if the
negative sequence current is higher than the preset starting value.
In the negative sequence overcurrent protection function, definite-time or inverse-time
characteristics are implemented, according to IEC or IEEE standards. The function
evaluates a single measured current, which is the RMS value of the fundamental Fourier
component of the negative sequence current. The characteristics are harmonized with IEC
60255-151, Edition 1.0, 2009-08.
