ABB Relion 615 series, Technical Manual

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values during the motor start-up. The excessive I
2
values are caused by incorrectly
connected phases, which in turn makes the motor rotate in the opposite direction.
The function contains a blocking functionality. It is possible to block function outputs,
timer or the function itself, if desired.
4.4.3.4 Operation principle
The function can be enabled and disabled with the Operation setting. The corresponding
parameter values are “Enable” and “Disable”.
The operation of 46R can be described with a module diagram. All the modules in the
diagram are explained in the next sections.
PICKUP
TRIP
Level
detector
BLOCK
I
2
Timer
t
GUID-F0B4B5EF-8B3C-4967-9818-24DACE686FC8-ANSI V1 EN
Figure 304: Functional module diagram
Level detector
The level detector compares the negative-sequence current to the set Pickup value . If the I
2
value exceeds the set Pickup value , the level detector sends an enabling signal to the timer
module.
Timer
Once activated, the timer activates the
PICKUP
output. When the operation timer has
reached the set Trip delay time value, the TRIP output is activated. If the fault disappears
before the module trips, the reset timer is activated. If the reset timer reaches the value of
200 ms, the operation timer resets and the
PICKUP
output is deactivated.
The timer calculates the pickup duration value PICKUP_DUR, which indicates the ratio
of the pickup situation and the set trip time. The value is available in the monitored data
view.
4.4.3.5 Application
The rotation of a motor in the reverse direction is not a desirable operating condition.
When the motor drives fans and pumps, for example, and the rotation direction is reversed
due to a wrong phase sequence, the driven process can be disturbed and the flow of the
cooling air of the motor can become reversed too. With a motor designed only for a
Section 4
1MAC059074-MB A
Protection functions
600 615 series ANSI
Technical Manual