9.5 Loss of voltage check LOVPTUV (27) SEMOD171868-1 v29.5.1 IdentificationSEMOD171954-2 v2Function description IEC 61850identificationIEC 60617identificationANSI/IEEE C37.2device numberLoss of voltage check LOVPTUV - 279.5.2 Application SEMOD171876-4 v3The trip of the circuit breaker at a prolonged loss of voltage at all the three phases isnormally used in automatic restoration systems to facilitate the system restoration aftera major blackout. Loss of voltage check (LOVPTUV, 27) generates a TRIP signal onlyif the voltage in all the three phases is low for more than the set time. If the trip to thecircuit breaker is not required, LOVPTUV (27) is used for signallization only throughan output contact or through the event recording function.9.5.3 Setting guidelines SEMOD171929-4 v5Loss of voltage check (LOVPTUV, 27) is in principle independent of the protectionfunctions. It requires to be set to open the circuit breaker in order to allow a simplesystem restoration following a main voltage loss of a big part of the network and onlywhen the voltage is lost with breakers still closed.All settings are in primary values or per unit. Set operate level per phase to typically70% of the global parameter VBase level. Set the time delay tTrip=5-20 seconds.9.5.3.1 Advanced users settings SEMOD171929-8 v4For advanced users the following parameters need also to be set. Set the length of thetrip pulse to typical tPulse=0.15 sec. Set the blocking time tBlock to block Loss ofvoltage check (LOVPTUV, 27), if some but not all voltage are low, to typical 5.0seconds and set the time delay for enabling the function after restoration tRestore to 3 -40 seconds.Section 9 1MRK 511 401-UUS AVoltage protection258 Bay control REC670 2.2 ANSIApplication manual
