Instruction manual
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AQ G3x7 Generator protection IED
61 (211
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Characteristics
This module
•
Calculates the current threshold value based on the Fourier components of the phase
voltages;
•
Calculates required time delay based on the Fourier components of the phase currents;
•
Decides the generation of the starting signal in the individual phases;
•
Decides the generation of the trip command in the individual phases.
Decision logic
The decision logic module combines the status signals to generate the trip command of the
function.
The signals and commands are generated only if neither the general blocking signal nor the
blocking signal of the voltage transformer supervision function stops the operation.
The general start signal indicates the starting in any of the phases, the general trip command
is generated if the current in any of the phases is above the calculated threshold value and
the time delay expired.
Figure 3-33: The function block of the voltage dependent overcurrent protection function.
