Instruction manual
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AQ G3x7 Generator protection IED
165 (211
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3.3.3
D
EAD LINE DETECTION FUNCTION
The “Dead Line Detection” (DLD) function generates a signal ind
icating the dead or live
state of the line. Additional signals are generated to indicate if the phase voltages and
phase currents are above the pre-defined limits.
The task of the “Dead Line Detection” (DLD) function is to decide the Dead line/Live line
state.
Criteria of “Dead line” state
: all three phase voltages are below the voltage setting value
AND all three currents are below the current setting value.
Criteria of “Live line” state
: all three phase voltages are above the voltage setting value.
Dead line detection function is used in the voltage transformer supervision function also as
an additional condition.
In the figure below is presented the operating logic of the dead line detection function.
DLD_StUL3_GrI_
Dead line
Detection
UL2Four
UL1Four
UL3Four
IL2Four
IL1Four
IL3Four
Parameters
DLD_StUL2_GrI_
DLD_StUL1_GrI_
DLD_StIL3_GrI_
DLD_StIL2_GrI_
DLD_StIL1_GrI_
Status signal
Figure 3-98: Principal scheme of the dead line detection function
1.1.1.1
The symbol of the function block in the AQtivate 300 software
The function block of the dead line detection function is shown in figure bellow. This block
shows all binary input and output status signals that are applicable in the AQtivate 300
software.