ABB RELION 650 SERIES, Technical Manual

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6.1.7.1 Filtering
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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.
6.1.7.2 Distance measuring zones
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The different fault loops within the IED are of full scheme type, which means that
earth fault loop for phase-to-earth faults and phase-to-phase faults for forward and
reverse faults are executed in parallel.
Figure 31 presents an outline of the different measuring loops for the six distance
zones.
IEC05000458-2-en.vsd
L1-N L2-N L3-N
L1-N L2-N L3-N
L1-N L2-N L3-N
L1-N L2-N L3-N
L1-L2 L2-L3 L3-L1
L1-L2 L2-L3 L3-L1
L1-L2 L2-L3 L3-L1
L1-L2 L2-L3 L3-L1
L1-N L2-N L3-N L1-L2 L2-L3 L3-L1
Zone 1
Zone 2
Zone 3
Zone 4
Zone 5
L1-N L2-N L3-N L1-L2 L2-L3 L3-L1
Zone RV
IEC05000458 V2 EN-US
Figure 31: The different measuring loops at phase-to-earth fault and phase-to-
phase fault
Each distance protection zone performs like one independent distance protection
function with six measuring elements.
Transients from CVTs may have a significant impact on the transient overreach of
a distance protection. At the same time these transients can be very diverse in
nature from one type to the other; in fact, more diverse than can be distinguished
by the algorithm itself in the course of a few milliseconds. So, a setting (
CVTtype )
is introduced in order to inform the algorithm about the type of CVT applied and
Section 6
1MRK 506 382-UEN A
Impedance protection
94 Line distance protection REL650 2.2 IEC
Technical manual