ABB RED650, Руководство по применению

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This setting opens an opportunity to enable phase-to-earth measurement for phase-
to-phase-earth faults. It determines the level of residual current (3I0) above which
phase-to-earth measurement is activated (and phase-to-phase measurement is
blocked). The relations are defined with the equation.
0 max
Re
3
100
ph
IN leasePE
I I
× ³ ×
EQUATION2548 V1 EN-US
(Equation 75)
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.
One specific situation where the INReleasePE setting should be altered is for cross-
country faults in high impedance earthed networks, in order to make sure that
operation is phase-to-earth. This is particularly important when using phase
preference logic, since it is only working per phase, not for phase-to-phase
measurement. The limit should be set so that it will be exceeded during a cross-
country fault.
7.1.3.10 ZMMMXU settings
GUID-42F340C5-93CC-40AE-B67D-DC1B7D0520DA v1
ZZeroDb
Minimum level of impedance in % of range ( ZMax-ZMin ) used as indication of
zero impedance (zero point clamping). Measured values below ZZeroDb are forced
to zero.
ZHiHiLim , ZHiLim , ZLowLim and ZLowLowLim
All measured values are supervised against these four settable limits. It provides
the attribute "range" in the data class MV (measured value) with the type
ENUMERATED (normal, high, low, high-high and low-low) in
ZMFPDIS.ZMMMXU.
ZLimHys
Hysteresis value in % of range ( ZMax-ZMin ), common for all limits. It is used to
avoid the frequent update of the value for the attribute “range”.
1MRK 505 393-UEN B
Section 7
Impedance protection
Line differential protection RED650 2.2 IEC 133
Application manual