Automatic Adjustment of Transformer and Phase-Shifter Taps in the Newton Power Flow

In recent years, Newton's method has been generally accepted as a superior algorithm for solving power flow problems. But the introduction of generator var limits, area-interchange control, load-tap- changing (LTC) transformers, and variable phase shifting transformers has significantly increased the solution times (compared with a fixed system). This paper shows how LTC transformers and variable phase-shifting transformers may be automatically adjusted by the Newton algorithm, thus complementing a previous inclusion of the area interchange control variables within the Newton algorithm [1]. Tests of the new method for adjusting LTC transformers and phase shifters indicate a significant overall saving in solution time.