5.2.2 IntroductionThe 1Ph High impedance differential protection HZPDIF function can be usedwhen the involved CT cores have the same turn ratio and similar magnetizingcharacteristics. It utilizes an external summation of the currents in theinterconnected CTs and a series resistor and a voltage dependent resistor externallyto the IED.HZPDIF can be used as high impedance REF protection.5.2.3 Function blockIEC05000363-2-en.vsdHZPDIFISI*BLOCKBLKTRTRIPALARMMEASVOLTIEC05000363 V2 ENFigure 44: HZPDIF function block5.2.4 SignalsTable 23:HZPDIF Input signalsName Type Default DescriptionISI GROUPSIGNAL- Group signal for current inputBLOCK BOOLEAN 0 Block of functionBLKTR BOOLEAN 0 Block of tripTable 24:HZPDIF Output signalsName Type DescriptionTRIP BOOLEAN Trip signalALARM BOOLEAN Alarm signalMEASVOLT REAL Measured RMS voltage on CT secondary sideSection 5 1MRK 502 034-UEN -Differential protection96Technical Manual
