ABB RELION REX640 Technical Manual page 503

1MRS759142 F
Timer
Once activated, the timer activates the START output. The time characteristic is
according to DT. When the operation timer has reached the value set with the
Operate delay time setting, the OPERATE output is activated. If the fault disappears
before the module operates, the reset timer is activated. If the reset timer reaches
the value set with the
the START output is deactivated. The timer calculates the start duration value
START_DUR, which indicates the percentage ratio of the start situation and the set
operation time. The value is available in the monitored data view.
Blocking logic
There are three operation modes in the blocking function. The operation modes
are controlled by the BLOCK input and the global setting in Configuration >
System > Blocking mode which selects the blocking mode. The BLOCK input can
be controlled by a binary input, a horizontal communication input or an internal
signal of the protection relay's program. The influence of the BLOCK signal activation
is preselected with the global setting
The
mode, the operate timer is frozen to the prevailing value, but the OPERATE output
is not deactivated when blocking is activated. In the "Block all" mode, the whole
function is blocked and the timers are reset. In the "Block OPERATE output" mode,
the function operates normally but the OPERATE output is not activated.
4.2.4.6 Neutral admittance characteristics
The applied characteristic should always be set to cover the total admittance of
the protected feeder with a suitable margin. However, more detailed setting value
selection principles depend on the characteristic in question.
The forward and reverse boundary settings should be set so that the forward
setting is always higher than the reverse setting and that there is space between
them.
Overadmittance characteristic
The overadmittance criterion is enabled with the setting
"Yo". The characteristic is a circle with the radius defined with the
setting. For the sake of application flexibility, the midpoint of the circle can be
moved away from the origin with the
settings. Default values for
that is, the characteristic is an origin-centered circle.
Operation is achieved when the measured admittance moves outside the circle.
The overadmittance criterion is typically applied in unearthed networks, but it can
also be used in compensated networks, especially if the circle is set off from the
origin.
REX640
Technical Manual
Reset delay time setting, the operation timer resets and
Blocking mode setting has three blocking methods. In the "Freeze timers"
The settings defining the admittance characteristics are given in primary
milliSiemens.
Blocking mode .
Circle conductance and Circle susceptance
Circle conductance and Circle susceptance are 0.0 mS,
Protection functions
Operation mode set to
Circle radius
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