Protected ObjectL1 L2 L3IEDINPINSINS2IEC11000029-4-en.vsdx43CT 1000/1a)b)(+)(+)(-)(-) (+)(-)1 SMAI2BLOCKREVROT^GRP2L1^GRP2L2^GRP2L3^GRP2NAI3PAI1AI2AI3AI4AINIEC11000029 V4 EN-USFigure 14: Connections for single-phase CT inputWhere:1) shows how to connect single-phase CT input in the IED.2) is TRM where these current inputs are located. It shall be noted that for all these current inputsthe following setting values shall be entered.For connection (a) shown in figure 14:CTprim = 1000 ACTsec = 1ACTStarPoint=ToObjectFor connection (b) shown in figure 14:CTprim = 1000 ACTsec = 1ACTStarPoint=FromObject3) shows the connection made in SMT tool, which connect this CT input to the fourth input channelof the preprocessing function block 4).4) is a Preprocessing block that has the task to digitally filter the connected analog inputs andcalculate values. The calculated values are then available for all built-in protection and controlfunctions within the IED, which are connected to this preprocessing function block.If frequency tracking and compensation is required (this feature is typically required only forIEDs installed in the power plants) then the setting parametersDFTReference shall be setaccordingly.4.2.3 Relationships between setting parameter Base Current, CTrated primary current and minimum pickup of a protection IEDGUID-8EB19363-9178-4F04-A6AC-AF0C2F99C5AB v1Note that for all line protection applications (e.g. distance protection or line differentialprotection) the parameter Base Current (i.e. IBase setting in the IED) used by the relevantprotection function, shall always be set equal to the largest rated CT primary current among allSection 4 1MRK 504 158-UEN AAnalog inputs42Application manual
