A thyristor-controlled regulating transformer.
Thesis DisciplineElectrical Engineering
Degree GrantorUniversity of Canterbury
Degree NameDoctor of Philosophy
Based on the principle of the voltage regulating transformer, a thyristor-controlled voltage regulator which effects both magnitude and phase shift control is proposed. Two back-to-back thyristor switches per phase are required, and the device provides fast and continuously variable voltage magnitude and phase shift control at the expense of some waveform distortion. A dynamic simulation computer programme, which is based on the state-space approach, is developed. A three-phase control unit, to control the thyristor switchings on each phase, is described and the theoretical waveforms are verified by both experimental tests and digital computer studies. Consideration is also given to the harmonic content produced. Applications of the proposed thyristor-controlled regulating transform to the problems of voltage regulation, power transfer control and improvement in the transient stability of interconnected systems are also presented.