Section 10 Frequency protection10.1 Underfrequency protection SAPTUF IP15746-1 v310.1.1 IdentificationM14865-1 v5Function description IEC 61850identificationIEC 60617identificationANSI/IEEE C37.2device numberUnderfrequency protection SAPTUFf <SYMBOL-P V1 EN-US8110.1.2 Functionality M13349-3 v13Underfrequency occurs as a result of a lack of generation in the network.Underfrequency protection (SAPTUF) measures frequency with high accuracy, andis used for load shedding systems, remedial action schemes, gas turbine startup andso on. Separate definite time delays are provided for operate and restore.SAPTUF is provided with undervoltage blocking.The operation is based on positive sequence voltage measurement and requires twophase-phase or three phase-neutral voltages to be connected. For information abouthow to connect analog inputs, refer to Application manual/IED application/Analog inputs/Setting guidelines.10.1.3 Function block M13352-3 v6IEC06000279_2_en.vsdSAPTUFU3P*BLOCKBLKTRIPBLKRESTTRIPSTARTRESTOREBLKDMAGNFREQIEC06000279 V2 EN-USFigure 126: SAPTUF function block1MRK 505 394-UEN A Section 10Frequency protectionLine differential protection RED650 2.2 IEC 267Technical manual
