Instruction manual
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AQ G3x7 Generator protection IED
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The inputs of the function are the Fourier basic harmonic components of the zero sequence
current and those of the zero sequence voltage. In the figure below is presented the
structure of the residual directional overcurrent algorithm.
Figure 3-36: Structure of the residual directional overcurrent algorithm.
The block of the directional decision generates a signal of TRUE value if the UN=3Uo zero
sequence voltage and the IN=-3Io current is sufficient for directional decision, and the angle
difference between the vectors is within the preset range. This decision enables the output
start and trip signal of the residual overcurrent protection function block.