ABB RELION REX640, Техническое руководство, Страница: 1227 / 1960

typically accelerates the tripping in case of energizing a feeder onto a fault. Without
CVPSOF, this tripping is normally performed by the normal time-graded protection
or alternatively by the time-delayed local backup protection, for which operating
times are considerably longer than with CVPSOF tripping.
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.
5.8.7 Signals
1MRS759142 F Protection related functions
REX640
Technical Manual
1227