Study Of Novel Principle Of Multi Criteria And Comprehensive Main Protection For Transformer

Aprotectiveschemeofmultilevelintimedomainandmulticriteriaisbroughtforwardin this paper. On the one hand, when the characteristic of fault is obvious, the method of fastdistinguishing internal fault from external fault of transformer works with the algorithm ofquicklydifferentiating inrush current from internal current to carryout quick-characteristic ofdifferential protection;when the characteristic of fault is ambiguous, to improve reliabilityofdifferential protection, it is necessary to extend the data window, and utilize the method ofsynthetic negative current polarity protection for identifying internal fault from external faultof transformer and adopt a series of ways of distinguishing inrush current from internalcurrent for transformer;on the other hand, with the time of the two ways of identifyinginternal fault from external fault of transformer and three methods of distinguishing inrushcurrent from internal current for transformer increasing, the sensitivity of these methods gethigher and higher. Several criteria can cooperate with each other automatically within onecycleafterinitiate,sothattherapidityandreliabilitycanreachcorrespondence.