4.2.2 Setting of current channels SEMOD55055-16 v5The direction of a current to the IED is depending on the connection of the CT. Unlessindicated otherwise, the main CTs are supposed to be star connected and can be connectedwith the earthing point to the object or from the object. This information must be set in theIED. The convention of the directionality is defined as follows: A positive value of current,power, and so on means that the quantity has the direction into the object and a negativevalue means direction out from the object. For directional functions the direction into theobject is defined as Forward and the direction out from the object is defined as Reverse. Seefigure 3A positive value of current, power, and so on (forward) means that the quantity has a directiontowards the object. - A negative value of current, power, and so on (reverse) means a directionaway from the object. See figure 3.Protected ObjectLine, transformer, etcForwardReverseDefinition of directionfor directional functionsMeasured quantity ispositive when flowingtowards the objecte.g. P, Q, IReverseForwardDefinition of directionfor directional functionse.g. P, Q, IMeasured quantity ispositive when flowingtowards the objectSet parameterCTStarPointCorrect Setting is"ToObject"Set parameterCTStarPointCorrect Setting is"FromObject"en05000456.vsdIEC05000456 V1 EN-USFigure 3: Internal convention of the directionality in the IEDWith correct setting of the primary CT direction,CTStarPoint set toFromObject orToObject, apositive quantities always flowing towards the object and a direction defined as Forwardalways is looking towards the object. The following examples show the principle.4.2.2.1 Example 1 SEMOD55055-23 v5Two IEDs used for protection of two objects.Section 4 1MRK 505 355-UEN AAnalog inputs32Application manual
