Name Type Values (Range) Unit Description
ZBANGIM REAL - deg ZB Angle, magnitude of instantaneous
value
ZCIMAG REAL - Ohm ZC Amplitude, magnitude of
instantaneous value
ZCANGIM REAL - deg ZC Angle, magnitude of instantaneous
value
7.8.7 Operation principle
GUID-2432C04F-62E4-4817-9900-C830306FB4B0 v3
Settings, input and output names are sometimes mentioned in the following text
without its zone suffix (i.e. BLKZx instead of BLKZ3) when the description is equally
valid for all zones.
7.8.7.1 Filtering
GUID-16B5060B-101C-402A-BF25-06E70FDD7836 v2
Practically all voltage, current and impedance quantities used within the ZMFPDIS function are
derived from fundamental frequency phasors filtered by a half cycle filter.
The phasor filter is frequency adaptive in the sense that its coefficients are changed based on the
estimated power system frequency.
A half cycle filter will not be able to reject both even and odd harmonics. So, while odd harmonics
will be completely attenuated, accuracy will be affected by even harmonics. Even harmonics will
not cause the distance zones to overreach however; instead there will be a slightly variable
underreach, on average in the same order as the magnitude ratio between the harmonic and
fundamental component.
7.8.7.2 Distance measuring zones
GUID-74B12BB1-FE0A-4DE4-BDBE-159A438D396B v4
The execution of the different fault loops within the IED are of full scheme type, which means that
ground fault loop for phase-to-ground faults and phase-to-phase faults for forward and reverse
faults are executed in parallel.
Figure
148 presents an outline of the different measuring loops for the six distance zones.
Section 7 1MRK 502 066-UUS B
Impedance protection
302
Technical manual
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