Sepam - HV/MV Protection and control units (ENG) - Trinet

Differential current and through currentOperationThis function gives the rms value of the followingcurrents:c differential currents Id of the 3 phases:v Id1 = I1 - I1’v Id2 = I2 - I2’v Id3 = I3 - I3’.c through currents It of the 3 phases:v It1 = I1 + I1’2v It2 = I1 + I1’2v It3 = I1 + I1’2It is based on measurement of the fundamentalcomponent. When combined with motor generatordifferential protection (ANSI code 87M/87G,function n° F621), this function gives the valuesof the differential currents and through currentsfor the 3 phases, measured and stored whenthe motor differential protection trips:v Trip Id1, Trip Id2, Trip Id3,v Trip It1, Trip It2, Trip It3.Storage of the values is activated by the controllogic K855 coil.CharacteristicsId and Itmeasurement range 0.015 In to 24 In (1)unitaccuracy (2)pocket terminal formatresolutionrefresh interval(1)In nominal rating set in the status menu.(2)at In, in reference conditions (IEC 60255-6).SensorsThese measurements are related to the differentialcurrents Id and through currents It of the I and I’currents connected to the following connectors:sensor connectorcurrent I current I’CT 2B 3BA or kA±5% or ±1 digit3 significant digits0.1 A or 1 digit1 second (typical)ReadoutThe measurements may be accessed via:c the pocket terminal, add. reading menu,Idiff./Ithrough heading.The Trip Id and Trip It measurements are reset by:c the clear button on the pocket terminal,c the control logic K856 coil.Metering functions1/17