0
max
Re
3
100
ph
IN
leasePE
I
I
×
³
×
EQUATION2548 V1 EN-US
(Equation 356)
Where:
INReleasePE
the setting for the minimum residual current needed to enable operation in the phase-to-
earth fault loops in %
I
phmax
the maximum phase current in any of the three phases
By default, this setting is set excessively high to always enable phase-to-phase measurement
for phase-to-phase-earth faults. This default setting value must be maintained unless there
are very specific reasons to enable phase-to-earth measurement. Even with the default setting
value, phase-to-earth measurement is activated whenever appropriate, like in the case of
simultaneous faults: two earth faults at the same time, one each on the two circuits of a
double line.
7.13
High speed distance protection for series
compensated lines ZMFCPDIS
GUID-ED71CF5A-1453-4F2F-9C64-3A73C59EA948 v3
7.13.1
Identification
GUID-0F03DA72-0687-4762-91CB-EC8E59B86E06 v2
Function description
IEC 61850
identification
IEC 60617
identification
ANSI/IEEE C37.2
device number
High speed distance protection zone
(zone 1-6)
ZMFCPDIS
S00346 V1 EN-US
21
7.13.2
Application
IP14961-1 v2
GUID-12188AB4-5922-428B-86F5-5F3897D29807 v3
Sub-transmission networks are being extended and often become more and more complex,
consisting of a high number of multi-circuit and/or multi terminal lines of very different
lengths. These changes in the network will normally impose more stringent demands on the
fault clearing equipment in order to maintain an unchanged or increased security level of the
power system.
The high speed distance protection function (ZMFCPDIS) in the IED is designed to provide sub-
cycle, down to half-cycle operate time for basic faults. At the same time, it is specifically
designed for extra care during difficult conditions in high voltage transmission networks, like
faults on long heavily loaded lines and faults generating heavily distorted signals. These faults
are handled with outmost security and dependability, although sometimes with reduced
operating speed.
7.13.2.1
System earthing
GUID-FC9BF10E-8CA1-4B23-887D-2EAB6A2A0A6E v1
The type of system earthing plays an important role when designing the protection system.
Some hints with respect to distance protection are highlighted below.
Section 7
1MRK 505 343-UEN B
Impedance protection
324
Application manual
Summary of Contents for Relion 670 series
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