Table 377: 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 378: LOVPTUV (27) Non group settings (basic)
Name Values (Range) Unit Step Default Description
GlobalBaseSel 1 - 12 - 1 1 Selection of one of the Global Base Value
groups
9.7.6 Operation principle
SEMOD171765-4 v6
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 status and the function has been blocked from the HMI test menu.
(
Blocked
=
Yes
).
Section 9 1MRK 502 066-UUS B
Voltage protection
662
Technical manual
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