Basics of power factor measurements on high voltage stator bars and stator windings

This article is a tutorial on power factor (PF) measurements on high voltage stator bars and coils and describes the basic theory associated with this important test method. In addition, the most commonly used measuring techniques and typical equipment setup used to make PF measurements are described. The coil manufacturing industry has a lot of experience performing this test and had a major part in updating the current standard. Although measured values are a function of the coil insulation system, some typical trends in measured values are described.