Radio Frequency Response of a Large Turbine-Generator Stator Winding

Long term experience with on-line radio frequency monitoring of large turbine generators has shown a need for increased understanding of the propagation of arc generated radio frequency signals in a stator winding. This paper presents the results of an on going research program designed to obtain an increased understanding of radio frequency arc detection in large turbine generators. Test results from AC arcing response and sinewave response measurements made on a generator stator are presented in addition to the results obtained from a computer circuit analysis performed on a radio frequency circuit model of a portion of the same generator stator. These results led to a better understanding of RF arc signal propagation and helped to identify improved detection techniques. Three RF measurement techniques were studied for both the measurements and calculations, resulting in good agreement. Arc voltage detection sensitivity calculations give a minimum detectable level of arc voltage for each RF measurement technique.