A field-circuit approach to the design oriented evaluation of the no-load voltage harmonics of salient pole synchronous generators

The standards establish definite limits on the waveform distortion of the no-load voltage of the salient-pole synchronous generators, by means of the total harmonic distortion (THD) and the telephonic harmonic factor (THF): the constructional measures suited to reduce this distortion are numerous, and it is important to evaluate their effects during the design. A method for the calculation of the no-load voltage distortion, taking into account the presence of the teeth, the winding and pole shoe characteristics, the saturation in all the magnetic branches and the skewing between stator and rotor is described and discussed. An example of application is shown and the effect of some constructional measures is analysed.