POWER SYSTEMS VOLTAGE SUPPORT AND DISTORTION CORRECTION USING SWITCHING COMPENSATORS

For power systems reactive power control and distortion correction several conceptual options are available. Based on state-of-the-art technology, on-line implementation of time-domain compensation solution to harmonically polluted power system is shown to be a viable option. This also has the advantage of controlling reactive power at mains frequency. In this paper an engineering overview of currently available technology for time-domain and frequency- domain approaches to distortion correction is presented. Emphases is given to control algorithms and hardware /software requirements of error sawtooth comparison and hysteretic control strategies. Major experimental result obtained from on-line implementation of an enhanced error sawtooth algorithm on a 5.5kVA switching circuit are demonstrated to show the effectiveness of the time-domain control algorithm in distortion correction as well as in providing lagging or leading vars for fundamental voltage control. Discussion of the application switching compensators will also briefly present the progress on utilizing multiple stage series or parallel connection of low-power low-switching rate power switching circuit modules to meet the requirements of large scale power systems harmonic distortion problems.