ABB RED615 Technical Manual page 540

Section 4
Protection functions
534
Table 451: Operation mode types
Operation Mode
"Under"
"Over"
The Absolute hysteresis setting can be used for preventing unnecessary oscillations
if the input signal is slightly above or below the Start value setting. After leaving
the hysteresis area, the start condition has to be fulfilled again and it is not
sufficient for the signal to only return to the hysteresis area. If the ENA_ADD input
is activated, the threshold value of the internal comparator is the sum of the Start
value Add and Start value settings. The resulting threshold value for the
comparator can be increased or decreased depending on the sign and value of the
Start value Add setting.
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 by Operate
delay time, the OPERATE output is activated. If the starting condition disappears
before the module operates, the reset timer is activated. If the reset timer reaches
the value set by Reset delay time, the operation timer resets and 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 functionality. The operation modes
are controlled by the BLOCK input and the global setting "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 IED program. The influence of the BLOCK signal activation is preselected
with the global setting Blocking mode.
The Blocking mode setting has three blocking methods. In the "Freeze timers"
mode, the operation timer is frozen to the prevailing value. 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.
Description
If the input signal AI_VALUE is lower than the
Start value setting, the level
set value of the
detector enables the timer module.
If the input signal AI_VALUE exceeds the set
value of the Start value setting, the level detector
enables the timer module.
1YHT530004D05 D
615 series
Technical Manual