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
7.9.7 Operation principle
GUID-913A0692-F0A7-4B4B-83B4-AC2A96B3A989 v2
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.
7.9.7.1 Filtering
GUID-0EA39CA3-6CDA-41B0-A178-E5800868A0C5 v1
Practically all voltage, current and impedance quantities used within the ZMFCPDIS 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; instead there will be a slightly variable underreach, on
average in the same order as the magnitude ratio between the harmonic and the fundamental
component.
7.9.7.2 Distance measuring zones
GUID-674FC410-9BA3-437E-8358-62E9B81D7B65 v2
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
172 presents an outline of the different measuring loops for the six distance zones.
A-G B-G C-G
A-G B-G C-G
A-G B-G C-G
A-G B-G C-G
A- B
B
-
C
C-A
A- B B
-C
C-
A
A- B B-C -A
A- B B-C
C
-A
A-G B-G C-G
A- B
B
-C
C
-A
Zone 1
Zone 2
Zone 3
Zone 4
Zone 5
C
Zone 6
A-G B-G C-G
A- B
B
-
C
C-A
ANSI05000458-2-en.vsd
ANSI05000458 V2 EN-US
Figure 172: The different measuring loops at phase-to-ground fault and phase-to-phase fault
1MRK 502 066-UUS B Section 7
Impedance protection
341
Technical manual
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