Nonexistence of Symmetric Model of Subharmonic Oscillations in Three-Phase Circuit-An Approach By Interval Computation

摘要

This paper describes how the symmetry of a three-phase circuit prevents the symmetric modes of several sub- harmonic oscillations. First, we make mathematically it clear that the generation of symmetrical 1/3l-subharmonic oscillations (l = 1, 2,…) are impossible in the three-phase circuit. As far as 1/(3l+1)-subharmonic oscillations (l = 1, 2,…) and 1/(3l+2)- subharmonic oscillations (l = 0, 1,…) are concerned, the former in negative-phase sequence sequence and the latter in positive-phase se- quence are shown to be impossible. Further, in order to confirm the above results, we apply the method of interval analysis to the circuit equations and obtain all steady state solutions with unsymmetric modes.