Instruction manual
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AQ G3x7 Generator protection IED
108 (211
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The outputs are the calculated positive-sequence impedances (R+jX) of the six measuring
current loops:
o
Impedances of the three phase-phase loops,
o
Impedances of the three phase-ground loops.
Table 3-41: Calculated values of the impedance module.
Z_CALC includes six practically identical software modules for impedance calculation:
o
The three routines of the phase group are activated by phase voltages, phase currents
and the zero sequence current calculated from the phase current.
o
The three routines for the phase-to-phase loops get line-to-line voltages calculated from
the sampled phase voltages and they get differences of the phase currents. They do not
need zero sequence currents for the calculation.
The calculated impedances are analogue outputs of the impedance protection function. They
serve the purpose of checking possibility at commissioning.