ABB Relion 670 Series Applications Manual page 238

Section 8
Voltage protection
8.5 Loss of voltage check LOVPTUV (27)
8.5.1 Identification
Function description
Loss of voltage check
8.5.2 Application
The trip of the circuit breaker at a prolonged loss of voltage at all the three phases is normally used in
automatic restoration systems to facilitate the system restoration after a major blackout. Loss of voltage
check (LOVPTUV, 27) generates a TRIP signal only if the voltage in all the three phases is low for more
than the set time. If the trip to the circuit breaker is not required, LOVPTUV (27) is used for signallization
only through an output contact or through the event recording function.
8.5.3 Setting guidelines
Loss of voltage check (LOVPTUV, 27) is in principle independent of the protection functions. It requires
to be set to open the circuit breaker in order to allow a simple system restoration following a main voltage
loss of a big part of the network and only when the voltage is lost with breakers still closed.
All settings are in primary values or per unit. Set operate level per phase to typically 70% of the global
parameter VBase level. Set the time delay tTrip=5-20 seconds.
8.5.3.1 Advanced users settings
For advanced users the following parameters need also to be set. Set the length of the trip pulse to
typical tPulse=0.15 sec. Set the blocking time tBlock to block Loss of voltage check (LOVPTUV, 27), if
some but not all voltage are low, to typical 5.0 seconds and set the time delay for enabling the function
after restoration tRestore to 3 - 40 seconds.
232
IEC 61850
identification
LOVPTUV
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IEC 60617 ANSI/IEEE C37.2
identification device number
- 27
1MRK 505 370-UUS Rev. K
SEMOD171868-1 v2
SEMOD171954-2 v2
SEMOD171876-4 v3
SEMOD171929-4 v5
SEMOD171929-8 v4
Busbar protection REB670
Application manual