ABB Relion 620 Series - Identification; Function Block; Functionality; Operation Principle

5.6 Automatic switch-onto-fault logic CVPSOF
5.6.1 Identification
Function description IEC 61850
identification
IEC 60617
identification
ANSI/IEEE C37.2
device number
Automatic switch-onto-fault logic
(SOF)
CVPSOF CVPSOF SOFT/21/50
5.6.2 Function block
Figure 440: Function block
5.6.3 Functionality
The automatic 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.
5.6.4 Operation principle
The function can be enabled and disabled with the
Operation setting. The
corresponding parameter values are "On" and "Off".
The operation of CVPSOF can be described by using a module diagram. All the
modules in the diagram are explained in the next sections.
1MRS757644 H
Protection related functions
620 series
Technical Manual
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