Table 132: LOVPTUV (27) Group settings (advanced)
Name Values (Range) Unit Step Default Description
tPulse 0.050 - 60.000 s 0.001 0.150 Duration of TRIP pulse
tBlock 0.000 - 60.000 s 0.001 5.000 Time delay to block when all 3ph voltages are
not low
tRestore 0.000 - 60.000 s 0.001 3.000 Time delay for enable the function after
restoration
Table 133: LOVPTUV (27) Non group settings (basic)
Name Values (Range) Unit Step Default Description
GlobalBaseSel 1 - 6 - 1 1 Selection of one of the Global Base Value
groups
7.4.6 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).
Section 7 1MRK 511 287-UUS A
Voltage protection
188
Technical manual
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