Operation Principle - ABB REC650 ANSI Technical Manual

Section 7
Voltage protection
Table 132: LOVPTUV (27) Group settings (advanced)
Name Values (Range)
tPulse 0.050 - 60.000
tBlock 0.000 - 60.000
tRestore 0.000 - 60.000
Table 133: LOVPTUV (27) Non group settings (basic)
Name Values (Range)
GlobalBaseSel 1 - 6
7.4.6
188
Unit Step
s 0.001
s 0.001
s 0.001
Unit Step
- 1

Operation principle

The operation of Loss of voltage check LOVPTUV (27) is based on line voltage
measurement. LOVPTUV (27) is provided with a logic, which automatically recognizes
if the line was restored for at least tRestore before starting the tTrip timer. All three phases
are required to be low before the output TRIP is activated. The PICKUP output signal
indicates pickup.
Additionally, LOVPTUV (27) is automatically blocked if only one or two phase voltages
have been detected low for more than tBlock.
LOVPTUV (27) operates again only if the line has been restored to full voltage for at least
tRestore. Operation of the function is also inhibited by fuse failure and open circuit
breaker information signals, by their connection to dedicated inputs of the function block.
Due to undervoltage conditions being continuous the trip pulse is limited to a length set by
setting tPulse.
The operation of LOVPTUV (27) is supervised by the fuse-failure function (BLKV input)
and the information about the open position (CBOPEN) of the associated circuit breaker.
The BLOCK input can be connected to a binary input of the IED in order to receive a block
command from external devices or can be software connected to other internal functions
of the IED itself in order to receive a block command from internal functions. LOVPTUV
(27) is also blocked when the IED is in test mode and LOVPTUV (27) has been blocked
from the HMI test menu (Blocked = Yes).
Default Description
0.150 Duration of TRIP pulse
5.000 Time delay to block when all 3ph voltages are
not low
3.000 Time delay for enable the function after
restoration
Default Description
1 Selection of one of the Global Base Value
groups
1MRK 511 287-UUS A
Technical manual