DirectionalityCTStartPoint defines if the CTs grounding point is located towards or from the protectedobject under observation. If everything is properly set power is always measured towardsprotection object.BusbarProtectedObjectP QANSI05000373_2_en.vsd52IEDANSI05000373 V2 ENFigure 290: Internal IED directionality convention for P & Q measurementsPractically, it means that active and reactive power will have positive values when theyflow from the busbar towards the protected object and they will have negative values whenthey flow from the protected object towards the busbar.In some application, for example, when power is measured on the secondary side of thepower transformer it might be desirable, from the end client point of view, to have actuallyopposite directional convention for active and reactive power measurements. This can beeasily achieved by setting parameter PowAngComp to value of 180.0 degrees. With suchsetting the active and reactive power will have positive values when they flow from theprotected object towards the busbar.FrequencyFrequency is actually not calculated within measurement block. It is simply obtained fromthe pre-processing block and then just given out from the measurement block as an output.14.1.8.3 Phase current measurement CMMXUThe Phase current measurement (CMMXU) function must be connected to three-phasecurrent input in the configuration tool to be operable. Currents handled in the function canbe calibrated to get better then class 0.5 measuring accuracy for internal use, on the outputsand IEC 61850. This is achieved by magnitude and angle compensation at 5, 30 and 100%Section 14 1MRK 506 335-UUS AMonitoring604Technical manual
