Instruction manual
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AQ G3x7 Generator protection IED
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Figure 3-28: Operating characteristics of the residual time overcurrent protection function.
tOP (seconds)
Theoretical operating time if G> GS (without additional time delay),
G
Measured value of the Fourier base harmonic of the residual current
GS
Pick-up setting
The structure of the algorithm consists of following modules. Fourier calculation module
calculates the RMS values of the Fourier components of the residual current.
Characteristics module compares the Fourier basic harmonic components of the residual
current into the setting value. Decision logic module generates the trip signal of the function.
In the figure below is presented the structure of the residual time overcurrent algorithm.
Figure 3-29: Structure of the residual time overcurrent algorithm.