Large Salient Pole Synchronous Machines Field Windings Diagnosis by Frequency Response

Frequency Response Analysis is a well-known technique for the diagnosis of power transformers. Currently, this technique is under research for its application in rotary electrical machines. This paper presents the application of FRA to the diagnosis of poles of the field winding of synchronous machines. Numerous tests have been performed with ground fault and inter-turn fault in a pole of the field winding of a large commercial size synchronous generator. This technique has been validated through numerous experimental laboratory tests in a pole of a 40 MVA synchronous generator with satisfactory results.