Instruction manual
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AQ G3x7 Generator protection IED
39 (211
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Figure 3-16 Operating characteristics of the definite time overcurrent protection function.
tOP (seconds)
Theoretical operating time if G> GS (without additional time delay),
G
Measured peak value or Fourier base harmonic of the phase currents
GS
Pick-up setting value
IDMT operating characteristics depend on the selected curve family and curve type. All of
the available IDMT characteristics follow
Equation 3-1 IDMT characteristics equation.
t(G)(seconds)
Theoretical operate time with constant value of G
k, c
constants characterizing the selected curve
α
constant characterizing the selected curve
G
measured value of the Fourier base harmonic of the phase currents