1MAC309294-MB F Section 4Protection functionsRER620 213Technical Manual4.3.5 Negative sequence overvoltage protection 474.3.5.1 Identification4.3.5.2 Function blockFigure 97: Function block4.3.5.3 FunctionalityThe negative-sequence overvoltage protection 47 is used to detect negative-sequenceovervoltage conditions. 47 is used for the protection of machines.The function picks up when the negative-sequence voltage exceeds the set limit. 47operates with the definite time (DT) characteristics.The function contains a blocking functionality. It is possible to block function outputs, thedefinite timer or the function itself, if desired.4.3.5.4 Operation principleThe function can be enabled and disabled with the Operation setting. The correspondingparameter values are Enable and Disable.The operation of negative sequence overvoltage protection can be described by using amodule diagram. All the blocks in the diagram are explained in the next sections.Figure 98: Functional module diagram. V 2 is used for representing negative phasesequence voltage.Level detectorThe calculated negative sequence voltage is compared with the set Pickup value setting. Ifthe value exceeds the set Pickup value, the level detector enables the timer.Function description IEC 61850identificationIEC 60617identificationANSI/IEEE C37.2device numberNegative sequence overvoltage protection NSPTOV U2> 47V 2BLOCKLeveldetectorTRIPPICKUPBlockinglogictTimer
