Instruction manual
–
AQ F3x0 Feeder protection IED
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The binary inputs influencing the operation of the distance protection function can be
selected by the user.
The outputs are the calculated positive-sequence impedances (R+jX) of the six measuring
current loops and, as different zero sequence current compensation factors can be set for
the individual zones, the impedances are calculated for each zone separately:
•
Impedances of the three phase-phase loops,
•
Impedances of the three phase-ground loops.
Z_CALC includes six practically identical software modules for impedance calculation:
•
The three members of the phase group are activated by phase voltages,
phase currents and the zero sequence current calculated from the phase
current and the zero sequence currents of the parallel line, as measured in a
dedicated input.
•
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.
Table 3-32 Calculated values of the impedance module.
Measured value
Dim.
Explanation
RL1+j XL1
ohm
Measured positive sequence impedance in the L1N loop, using the
zero sequence current compensation factor for zone 1
RL2+j XL2
ohm
Measured positive sequence impedance in the L2N loop, using the
zero sequence current compensation factor for zone 1
RL3+j XL3
ohm
Measured positive sequence impedance in the L3N loop, using the
zero sequence current compensation factor for zone 1
RL1L2+j XL1L2
ohm
Measured positive sequence impedance in the L1L2 loop
RL2L3+j XL2L3
ohm
Measured positive sequence impedance in the L2L3 loop
RL3L1+j XL3L1
ohm
Measured positive sequence impedance in the L3L1 loop
