IAIBICZerosequencefilterNegativesequencefilterVAVBVCZerosequencefilterNegativesequencefilterCurrZeroSeqCurrNegSeqab a>bab a>bab a>bab a>b3I0PU3I2PUVoltZeroSeqVoltNegSeqANDANDFuseFailDetZeroSeqFuseFailDetNegSeqSequence Detection3V0PU3V2PU3I03I23V03V2ANSI10000036-2-en.vsd0100 ms0100 msANSI10000036 V2 ENFigure 157: Simplified logic diagram for sequence detection partThe calculated values 3V0, 3I0, 3I2 and 3V2 are available as service values on local HMIand monitoring tool in PCM600.11.1.7.2 Delta current and delta voltage detectionA simplified diagram for the functionality is found in figure 158. The calculation of thechange is based on vector change which means that it detects both amplitude and phaseangle changes. The calculated delta quantities are compared with their respective setvalues DIPU and DVPU and the algorithm, detects a fuse failure if a sufficient change involtage without a sufficient change in current is detected in each phase separately. Thefollowing quantities are calculated in all three phases:• The change in voltage DV• The change in current DIThe internal FuseFailDetDVDI signal is activated if the following conditions are fulfilledfor a phase:1MRK 502 048-UUS A Section 11Secondary system supervision335Technical manual
