ABB RELION 620 Series Technical Manual page 841

1MRS757644 F
5.6.6
620 series
Technical Manual
An internal dead line detection check is provided to activate the function when the
voltage transformers are located on the feeder side. An initiation by the dead line
detection is highly recommended for the busbar configurations where more than one
circuit breaker at one feeder end can energize the protected feeder or the feeder can
also be energized from the other end.
Setting guidelines
Input START: If a distance zone is used for starting the switch-onto-fault function, the
zone has to be set to cover the entire protected feeder with a safety margin of minimum
20 percent. If the non-directional zone is not available, the internal Current & Voltage
criterion or the start signal from the GFC function can be used instead. If a non-
directional overcurrent is used for starting, the current setting must not be higher than
what is required for the non-delayed and dependable tripping for a close-in three-
phase fault during minimum source conditions. If the short-circuit current along the
feeder is considerably higher than the maximum load currents, it is possible that the
whole feeder length is covered by CVPSOF tripping. If it is required to delay the
tripping, for example, due to high inrush currents, the starting signal can be connected
to the START_DLYD input instead.
The Current dead Lin Val setting parameter is set to 20 percent of the base current by
default. The parameter must be set with a sufficient margin of 15...20 percent under
the minimum expected load current. The setting must still exceed the maximum
charging current of a feeder.
The Voltage dead Lin Val setting parameter is set to 70 percent of the base voltage by
default. This is a suitable setting in most cases, but it is recommended to check the
suitability in the actual application.
The Cur voltage Det time setting parameter is set to 0.02 seconds by default. This is
suitable in most applications. This delay can be coordinated, for example, with the
dead time settings of the AR shots to prevent the release of CVPSOF by the dead line
detection function when the high-speed autoreclosing is in progress.
The Dead line time setting parameter is set to 0.2 seconds by default. This is suitable
in most applications. The delay must not be set too short to avoid unwanted activations
during the transients in the system.
The SOTF reset time setting parameter is set to 1 second by default. This is suitable for
most applications.
Signals
Table 803: CVPSOF Input signals
Name Type
I_A SIGNAL
I_B SIGNAL
I_C SIGNAL
Table continues on next page
Protection related functions
Default Description
0 Phase A current
0 Phase B current
0 Phase C current
Section 5
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