Development and Field Testing of an Adaptive Power Factor Controller

The adaptive power factor controller (APFC) is a device that switches capacitors electronically to achieve almost unity power factor at the point of installation. It was designed and developed at the University of Washington (UW), and is being tested at the R&D facility of the Southern California Edison Company (SCE). It is particularly intended for loads with dynamically varying reactive power demands such as induction generators in wind power stations, or cyclically changing loads such as induction motors in process industries. It is also ideally suited for improving the power factor profile of a distribution line. The purposes of this paper are twofold: to explain the most recent design of the 50-kVAR APFC and to report the results of the field testing program on the device after it was installed at the terminals of a 50-kW three-phase induction generator located at the Dever Wind R&D site of SCE.