ABB RELION REX640 Technical Manual page 962

Section 4
Protection functions
956
A typical error is, for example, that the VT or CT poles are wrongly
connected. This is seen as a power flow opposite to that of the intended
direction. The Pol Reversal setting can be used to correct the situation.
By setting the value to "True", the measured apparent power is turned
180 degrees.
Level detector
Level detector compares the calculated value of the active power with a set Start
value. If the calculated value of the active power falls below Start value in the forward
direction or if the measured power is in the reverse direction, Level detector enables
the Timer module.
GUID-2B2F2DFD-796C-4237-BF96-2A14C4EDEDCC V1 EN
Figure 518: Operating characteristics of DUPPDPR with setting Start value
Timer
Once activated, Timer activates the START output. The time characteristics are
according to DT. When the operation timer has reached the value of Operate delay
time, the OPERATE output is activated. In a drop-off situation, that is, if the
underpower condition disappears before the operation delay is exceeded, the timer
reset state is activated. If the reset timer reaches the value set by Reset delay time, the
operation timer resets and the START output is deactivated.
Q
Non
Operating
operating
area
area
Start Value
1MRS759142 C
P
REX640
Technical Manual