Modeling of synchronous machines with damper windings for condition monitoring

In this paper, a method of modeling synchronous machines with damper windings based on the winding function approach (WFA) has been proposed. This method of machine analysis with the actual winding distribution does not require neglecting the harmonics of the winding distributions. The proposed model can be used to simulate the machine under faulty conditions such as broken damper bars and end ring, eccentricities and inter-turn faults. Given the geometry of the machine and its winding configuration, all the inductances are calculated as a function of the rotor position. The skewed rotor is included in the model and its smoothing effects on the waveforms are presented. Damper bar currents are studied under healthy and broken bar cases. The experimental results are presented and compared to the simulation results to verify the modeling. A special inside-out, round rotor synchronous machine is used for test and verification of the model. The field winding and the damper bars of this machine are mounted on the stator which makes it possible to monitor the bars and end ring currents directly and accurately without using flux probe.