ABB RET670 - Page 531

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ANSI07000189-1-en.vsd
ANSI07000189 V1 EN
Figure 216: Ground fault in Direct grounded system
Settings for Two step residual overvoltage protection
Operation: Disabled or Enabled
VBase is used as voltage reference for the voltage. The voltage can be fed to the IED in
different ways:
1. The IED is fed from a normal voltage transformer group where the residual
voltage is calculated internally from the phase-to-ground voltages within the
protection. The setting of the analogue input is given as VBase=Vph-ph.
2. The IED is fed from a broken delta connection normal voltage transformer group.
In an open delta connection the protection is fed by the voltage 3V0 (single input).
The Setting chapter in the application manual explains how the analog input needs
to be set.
3. The IED is fed from a single voltage transformer connected to the neutral point of
a power transformer in the power system. In this connection the protection is fed
by the voltage VN=V0 (single input). The Setting chapter in the application
manual explains how the analog input needs to be set. ROV2PTOV (59N) will
measure the residual voltage corresponding nominal phase-to-ground voltage for a
high impedance grounded system. The measurement will be based on the neutral
voltage displacement.
1MRK504116-UUS C Section 3
IED application
525
Application manual