Harmonic domain modelling of three phase thyristor-controlled reactors by means of switching vectors and discrete convolutions

T h e m a i n objective of this paper is to report on a newly developed three phase TCR model which is based on the use of harmonic switching vectors and discrete convolutions. This model is amenable to direct frequency domain operations and provides a fast and reliable means for assessing 6- and 12-pulse TCR plant performance at harmonic frequencies. The use of alternate time domain and frequency domain representations is avoided as well as the use of FFTs. I n this approach, each single phase unit of the TCR is modelled as a voltage-dependent harmonic Norton equivalent where all the harmonics and cross-couplings between harmonics are explicitly shown. This model is suitable for direct incorporation into the harmonic domain frame of reference where all the busbars, phases, harmonics and cross-couplings between harmonics are combined together for a unijied iterative solution through a Newton-Raphson technique exhibiting quadratic convergence.