Protective Elements
• Calculation of the residual voltage is only possible, when phase to neutral
voltage is applied to the voltage inputs.
At setting »
measured«
the quantities to be measured, i. e. Residual voltage
and the measured earth current have to be applied to the corresponding 4
th
measuring input.
All earth current protective elements can be planned user defined as non-directional or as directional stages. This
means, for instance, all 4 elements can be projected in forward/reverse direction. For each element the following
characteristics are available:
DEFT (UMZ) –
Definite Time-Overcurrent
NINV (IEC/AMZ) –
IEC Normal Inverse
VINV (IEC/AMZ) –
IEC Very Inverse
LINV (IEC/AMZ) –
IEC Long Time Inverse
EINV (IEC/AMZ) –
IEC Extremely Inverse
MINV (ANSI/AMZ) –
ANSI Moderately Inverse
VINV (ANSI/AMZ) –
ANSI Very Inverse
EINV (ANSI/AMZ) –
ANSI Extremely Inverse
RINV –
R Inverse
RXIDG
Thermal Flat
IT
I2T
I4T
Explanation:
The earth current can be measured either directly via a cable-type transformer or detected by a Holmgreen
connection. The earth current can alternatively be calculated from the phase currents; but this is only possible if the
phase currents are not ascertained by a V-connection.
The device can optionally be procured with a sensitive earth current measuring input.
718 MCDGV4 DOK-HB-MCDGV4-2E
t = Tripping delay
t-char = Time multiplier/tripping characteristic factor. The setting range depends
on the selected tripping curve.
IG = Fault current
IG> = If the pickup value is exceeded, the module/element starts to time out to trip .
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