Table 204:LOVPTUV (27) Group settings (advanced)Name Values (Range) Unit Step Default DescriptiontPulse 0.050 - 60.000 s 0.001 0.150 Duration of TRIP pulsetBlock 0.000 - 60.000 s 0.001 5.000 Time delay to block when all 3ph voltages arenot lowtRestore 0.000 - 60.000 s 0.001 3.000 Time delay for enable the function afterrestorationTable 205:LOVPTUV (27) Non group settings (basic)Name Values (Range) Unit Step Default DescriptionGlobalBaseSel 1 - 6 - 1 1 Selection of one of the Global Base Valuegroups8.4.6 Operation principleThe operation of Loss of voltage check LOVPTUV (27) is based on line voltagemeasurement. LOVPTUV (27) is provided with a logic, which automatically recognizesif the line was restored for at least tRestore before starting the tTrip timer. All three phasesare required to be low before the output TRIP is activated. The PICKUP output signalindicates pickup.Additionally, LOVPTUV (27) is automatically blocked if only one or two phase voltageshave been detected low for more than tBlock.LOVPTUV (27) operates again only if the line has been restored to full voltage for at leasttRestore. Operation of the function is also inhibited by fuse failure and open circuitbreaker 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 bysetting 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 blockcommand from external devices or can be software connected to other internal functionsof 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 blockedfrom the HMI test menu (Blocked = Yes).Section 8 1MRK 506 335-UUS AVoltage protection314Technical manual
