Harmonic overload definite time curve has settings facilities for independentpickup and time delay. It can be used as separate tripping stage or as an alarm stage.Both of these two harmonic overload stages are active during capacitor bankenergizing and are capable to properly measure and operate up to and including 9thharmonic.The internal logic for harmonic overload feature is shown in figure 101:IEC09000752-1-en.vsdOperationHOL=OnHOLDTU>aa>bbUPeakRMS [pu]ORBLKHOLBLOCKAND ttHOLDTTRHOLSTHOLOperationHOL=On ANDHOLIDMTU>aa>bbUPeakRMS [pu]kHOLIDMTtMaxHOLIDMTtMinHOLIDMTUPeakRMS [pu]ORORTRSTIDMTSTHDTLxSTHIDMLxANDBLKTRIEC09000752 V1 ENFigure 101: Simplified logic diagram for harmonic overload6.8.2.6 Capacitor reactive power overload featureReactive power overload protection feature will protect the capacitor bank fromreactive power overload conditions.The sub-function will use the reactive power values as input. The reactive powerinput values are calculated from the true RMS value of voltage and current. Thereactive power value is compared with the QOL> setting. When the reactive powervalue exceeds the QOL> setting the STQOL signal will be activated. The startsignal is delayed by the definite timer before activating the TRQOL signal. Theinternal logic diagram for this feature is shown in figure 102.1MRK 505 208-UEN B Section 6Current protection207Technical reference manual
