ABB Relion 670 Series Applications Manual page 230

Section 9
Voltage protection
ANSI07000189 V1 EN-US
Figure 100: Ground fault in Direct grounded system
9.3.3.6 Settings for two step residual overvoltage protection
Operation : Disabled or Enabled
VBase (given in GlobalBaseSel ) is used as voltage reference for the set pickup values. 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). Section
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=V
input needs to be set.
ROV2PTOV (59N) will measure the residual voltage corresponding to the nominal phase-to-ground
voltage for a high-impedance grounded system. The measurement will be based on the neutral
voltage displacement.
The setting parameters described below are identical for the two steps (
Therefore the setting parameters are described only once.
OperationStepn : This is to enable/disable operation of step n.
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.
Pickupn : Set operate overvoltage operation value for step n , given as % of residual voltage
corresponding to
224
(single input). Section
0
VBase :
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ANSI07000189-1-en.vsd
VBase =Vph-ph.
Analog inputs in the Application manual explains how the analog
Definite time or Inverse curve A or Inverse curve B or
1MRK 511 401-UUS F
M13853-21 v14
Analog inputs
n = step 1 and 2).
Bay control REC670
Application manual