Instruction manual
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AQ G3x7 Generator protection IED
133 (211
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The applied numerical method is solving the differential equation of the faulty loop, based
on the orthogonal components of the Fourier fundamental component vectors. The
calculation results complex impedances on the network frequency.
Figure 3-80 Principal scheme of the impedance calculation Z_CALC
The inputs are the Fourier components of:
•
the Fourier components of three phase voltages,
•
the Fourier components of three phase currents, parameters.
The outputs are the calculated positive sequence impedances (R+jX) of the three
measuring loops:
•
Impedances of the three phase-to-phase loops,
The calculated impedances of the Z_CALC module
Table 3-60 The measured (calculated) values of the Z_CALC module
Calculated value
Dim.
Explanation
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