x E3RfTCB 2(1- x) E3over- voltage protection 10%– 100%Differential0% – 30%CB 1 may not existRNN CB 1stator windinguTuNx E3Rf TransformerTCB 2(1- x) E3xNeutral point fundamental frequencyover-voltage protection 5% - 100%3rd harmonicdifferential0% - 30%CB 1 may not exist1 or 100 %RNNN CB 1stator windinguTuN 1 - x1 - xSamples of theneutral voltagefrom which thefundamental and3rd harmonicvoltages arefiltered outSamples of theterminal voltagefrom which the3rd harmonicvoltage is filteredoutIEC10000202-1-en.vsdIEC10000202 V1 ENFigure 256: Protection principles for STEFPHIZ function9.6.3 Function blockIEC11000211-1-en.vsdSTEFPHIZNEUTVOLTTERMVOLTCBCLOSEDBLOCKBLOCK3RDBLOCKUNTRIPTRIP3HTRIPUNSTARTSTART3HSTARTUNUT3UN3E3ANGLEDU3BU3UNIEC11000211 V1 ENFigure 257: STEFPHIZ function block1MRK502052-UEN B Section 9Voltage protection533Technical manual
