Figure. 5.3.8 - 99. Blocking application in the relay configuration.
In the example above, problems may arise if, during the start-up of a motor, a short-circuit fault occurs
while the overcurrent stage is blocked. This may make the fault clearing take longer as the relay still
considers the situation part of starting. In this case the following logic can be used to prevent
prolonging of the fault clearing time during the start-up of the motor. The main benefit of this logic is
that there is no need to spend another protection stage for short-circuit faults: the one stage that is set
below the starting current of the motor can also be used for short-circuits and overcurrent faults. See
below for a more detailed description of the logic in question.
Figure. 5.3.8 - 100. Motor start up overcurrent control logic.
Picture 1 (upper left). During a start-up, the MST1_MOTSTART signal is connected to the
LOGIC_OUT1 signal with an AND gate, and to the MST1_HIGHOC signal (the function's high
overcurrent detection) with a NOT gate. The overcurrent (I>) stage is blocked when a motor starts, but
the blocking is released if a high overcurrent is detected during the start-up process. The user can
choose to combine the high overcurrent detection with the NOC1_START signal with an AND gate, and
use the LOGIC_OUT2 signal (for example) to change the active setting group of the I> function to
operate instantly.
A
AQ
Q-M210
-M210
Instruction manual
Version: 2.04
126
Содержание AQ-M210
Страница 1: ...AQ M210 Motor protection IED Instruction manual ...
Страница 308: ...Figure 7 4 182 Example block scheme A AQ Q M210 M210 Instruction manual Version 2 04 307 ...
Страница 329: ...Figure 8 13 204 Panel cutout dimensions and device spacing A AQ Q M210 M210 Instruction manual Version 2 04 328 ...