ABB RELION REX640 Technical Manual page 1348

Supervision functions
Figure 765: Functional module diagram
Level detector
The
tophase voltages for supervision.
The voltage measurement can adapt the frequency to a range of 10...70 Hz.
Level detector supports one- or three-phase operation. Selection can be made with
setting
Table 1296: Functionality depending on Phase supervision
Value of
1 = A or AB
2 = B or BC
4 = C or CA
7 = A&B&C or AB&BC&CA
Timer
Once activated, Timer runs until the value of
time characteristic is according to DT. When the operation timer has reached the
value of
In a drop-off case, the remanent voltage returns to a value higher than the set value
Start value before Operate delay time is exceeded. Also, the timer reset state is
of
activated. The reset timer runs until the
duration of the voltage drop-off exceeds the set Reset delay time, the operate timer
is reset and the U_LOW output is deactivated.
The BLOCK input can be controlled with a binary input, a horizontal communication
input or an internal signal of the relay program. The activation of the BLOCK input
resets Timer and prevents the U_LOW output from being activated.
1348
U_A_AB
U_B_BC
U3P
U_C_CA
BLOCK
Voltage selection setting is used for selecting the phase-to-earth or phase-
Phase supervision .
Phase supervision
Operate delay time , the U_LOW output is activated.
Level
detector
Functionality
This selection implements single-phase voltage supervision
on the selected phase.
If the measured voltage of the supervised phase is lower
than the set value of the
enables the Timer module.
This selection implements three-phase voltage supervision.
The measured voltage of three supervised phases is com-
Start value setting.
pared against the
If the number of phases where the voltage is below the
setting matches the Num of phases setting, Level detector
enables the Timer module.
Operate delay time has elapsed. The
Reset delay time value is exceeded. If the
1MRS759142 F
Timer
U_LOW
t
Start value setting, Level detector
Technical Manual
REX640