Broken damper bar detection studies using flux probe measurements and time-stepping finite element analysis for salient-pole synchronous machines

Detection of broken damper bars in salient-pole synchronous machines has not been reported in the literature, because the cases of broken damper bars in salient-pole machines are not common. Stringent starting cycles in a pumped storage hydroelectric generator caused broken bars after almost 40 years of service. Development of on-line monitoring and detection of broken bars has been attempted by using flux probes attached to the stator bore surface for measurement of air gap flux waveform during acceleration from standstill to rated speed. Measurements of flux probe signals and finite element modeling and simulation of electromagnetic transients during acceleration of the pumped storage generator show the viability of the air gap flux probes for the development of an on-line monitoring method for broken damper bar detection.