ABB RELION 670 Series Applications Manual page 217

1MRK 505 337-UUS A
ANSI07000189 V1 EN-US
Figure 101: Ground fault in Direct grounded system
8.3.3.6 Settings for Two step residual overvoltage protection
Operation : Disabled or Enabled
VBase (given in GlobalBaseSel ) 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
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.
The below described setting parameters are identical for the two steps (
Therefore the setting parameters are described only once.
Characteristicn: Selected inverse time characteristic for step n . This parameter gives the type of
time delay to be used. The setting can be,
Inverse curve C or Prog. inv. curve . The choice is highly dependent of the protection application.
Application manual
ANSI07000189-1-en.vsd
VBase =Vph-ph.
Definite time or Inverse curve A or Inverse curve B or
Section 8
Voltage protection
M13853-21 v12
n = step 1 and 2).
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