ABB RELION REX640 Technical Manual page 1223

1MRS759142 F
5.8.2 Function block
Figure 696: Function block
5.8.3 Functionality
The switch-onto-fault function CVPSOF is a complementary function, especially to
the distance protection function (DSTPDIS), but it can also be used to complement
the non-directional or directional overcurrent protection functions (PHxPTOC,
DPHxPDOC).
CVPSOF accelerates the operation of the protection ensuring a fast trip when
the breaker is closed onto faulted feeder or bus. Without CVPSOF the measured
voltages may be too small for the impedance zones or the directional overcurrent
stages to operate reliably. This condition exists when the voltage transformers are
located in the feeder or the bus side to be energized and therefore the voltage
memory required for a correct directional measurement is not available.
5.8.4 Analog channel configuration
CVPSOF has two analog group inputs which must be properly configured.
Table 1165: Analog inputs
Input
I3P
U3P
There are a few special conditions which must be noted with the configuration.
1
Can be connected to GRPOFF if
"DLD disabled" or "Voltage"
2
Can be connected to GRPOFF if
"DLD disabled" or "Current"
REX640
Technical Manual
1
2
See the preprocessing function blocks in this document for the possible
signal sources. The GRPOFF signal is available in the function block called
Protection.
Operation mode is set to "Start" and Automatic SOTF Ini is set to
Operation mode is set to "Start" and Automatic SOTF Ini is set to
Description
Three-phase currents, necessary when Operation mode is
other than "Start"
Three-phase voltages, necessary when Operation mode is
other than "Start
Protection related functions
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