Current transformer selection guide

model orderorfeasibility study requestappendix 3for current transformerstypes :characteristics■ standard................................................................................................................................ _____________________■ rated insulation level ............................................................................................................. _____________________■ frequency.............................................................................................................................. _____________________■ short-circuit current .............................................................................................................. _____________________■ short-circuit time ................................................................................................................... _____________________■ rating of first primary............................................................................................................. _____________________■ rating of second primary....................................................................................................... _____________________■ rating of third primary............................................................................................................ _____________________kVHzkAsAAA■ 1 st secondary ............. metering ............. protection- associated primary rating(s) .................................................................................................. _____________________- first secondary current .......................................................................................................... _____________________ A- rated burden .......................................................................................................................... _____________________ VA- accuracy class ...................................................................................................................... _____________________- accuracy limiting factor ALF for secondary protection .......................................................... _____________________- for class X : formula required : Vk = f(Rct) ........................................................................ _____________________or knee-point voltage Vk ............................................................................... _____________________and secondary withstand Rct ........................................................................ _____________________magnetising current Iex (if necessary) ........................................................... _____________________■ 2 nd secondary ............. metering ............. protection- associated primary rating(s) .................................................................................................. _____________________- second secondary current ..................................................................................................... _____________________ A- rated burden .......................................................................................................................... _____________________ VA- accuracy class ...................................................................................................................... _____________________- accuracy limiting factor ALF .................................................................................................. _____________________- for class X : formula required : Vk = f(Rct) ........................................................................ _____________________or knee-point voltage Vk ............................................................................... _____________________and secondary withstand Rct ........................................................................ _____________________magnetising current Iex (if necessary) ........................................................... _____________________■ 3 rd secondary ............. metering ............. protection- associated primary rating(s) .................................................................................................. _____________________- third secondary current ......................................................................................................... _____________________ A- rated burden .......................................................................................................................... _____________________ VA- accuracy class ...................................................................................................................... _____________________- accuracy limiting factor ALF .................................................................................................. _____________________- for class X : formula required : Vk = f(Rct) ........................................................................ _____________________or knee-point voltage Vk ............................................................................... _____________________and secondary withstand Rct ........................................................................ _____________________magnetising current Iex (if necessary) ........................................................... _____________________VmAVmAVmAdate11/92- B•1•4 -revised08/95■ lead-sealable housing for secondary connections................................................................ _____________________■ support base......................................................................................................................... _____________________■ specific requirements 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_____________________.............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................TC 02/09/92page 20