Novel analytical solution to fundamental ferroresonance-part I: power frequency excitation characteristic

• Published in: IEEE transactions on power delivery Vol. 21; no. 2; pp. 788 - 793
• Main Authors: Li, Y., Shi, W., Li, F.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.04.2006; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Applied sciences; Approximation; Circuit breakers; Disturbances. Regulation. Protection; Electric potential; Electrical engineering. Electrical power engineering; Electrical power engineering; Electromagentic Transients Program (EMTP); Electromagnetic transients; Exact sciences and technology; Excitation; Ferroresonance; Fourier analysis; Fourier series; Frequency; Harmonics; Inductance; Inductors; Mathematical analysis; nonlinear circuits; potential transformer (PT); Power networks and lines; Power system harmonics; Power system transients; Substations; Voltage; Voltage transformers; Voltage transformer; inductance; EMTP; Fourier series; Inductor; Electromagentic Transients Program (EMTP); Non linear circuit; Experimental result; Electrical network; Approximation method; nonlinear circuits; potential transformer (PT); Numerical simulation; System simulation; Ferroresonance; Analytical solution; Comparative study
• ISSN: 0885-8977; 1937-4208
• DOI: 10.1109/TPWRD.2005.859303

This paper has highlighted a major problem with the traditional excitation characteristic (TEC) of nonlinear inductors, in that the TEC contains harmonic voltages and/or currents, and has been used the way as if it were made up of pure fundamental voltage and current. In comparison to the TEC, a new concept, namely the power frequency excitation characteristic (PEC), which contains no harmonics, has been put forward. Two methods have been presented in obtaining the PEC. The first method is based on Electromagnetic Transients Program simulation, resulting in discrete voltage and current pairs. This method essentially acts as a reference to validate the second one. The second method employs Fourier and Maclaurin series approximation techniques, and brings forth a simple yet effective analytical expression. The expression is proven to have satisfactory precision in the saturated region of the PEC, especially in the extremely saturated region.