Ferroresonance in power systems: Fundamental solutions

Abstract

Ferroresonance can occur in power transformers or reactors fed through capacitive coupling from neighbouring phases or lines. Ritz's method of harmonic balance is used to formulate an analytical solution to the problem of fundamental frequency ferroresonance. A two-term polynomial of order 11 is used to accurately represent the magnetisation characteristic of a typical high-voltage power transformer in the ferroresonance region. The derived closed-form solutions permit construction of a map defining the boundaries between safe and ferroresonant regions as a function of the system parameters. The transformer losses are included in the analysis and are shown to be an important factor in the demarcation of the ferroresonance regions.