M.Sc Thesis

M.Sc StudentSpitsa Vitaly
SubjectPower System Harmonics
DepartmentDepartment of Electrical and Computer Engineering
Supervisor PROFESSOR EMERITUS Abraham Alexandrovitz


Wide use of non-linear loads such as rectifiers, speed control systems, computers and fluorescent lighting in modern power systems causes harmonic distortion of currents and voltages and, as a result, can lead to failures and malfunction of consumers. Consequently, an investigation of harmonics is one of the most important goals in power system analysis.

The present research deals with a harmonic problem in the power systems. Main harmonic sources and power quality standards are described. A harmonic analysis method for three-phase balanced system is presented. Different elimination methods of parallel resonance, which prevent a significant voltage boost in the power systems, are described. Design stages of passive filters for a harmonic distortion reduction in the power systems are presented. The research contains an example of the power system harmonic analysis in the electrical network of industrial plant. An iterative algorithm, which allows to perform the above analysis considering the non-linear load input voltage harmonics influence on its current harmonic spectrum, is developed. Influence of input voltage harmonics on the induction motor performance is also investigated using a non-linear dynamic model. In the present research current harmonics of switch-mode power supplies and their propagation in the neutral wire were analyzed. The obtained results were verified by measurements which were carried out in the electrical network of the Electrical Engineering Department of the Technion.