| Summary: | Non-sinusoidal conditions are characteristic of modem electrical power systems. Technological advances
such as that of the rapidly developing solid-state technology has accelerated the nonlinear loading of
power systems. The thesis firstly reformulates and demonstrates multi-frequency power system analysis
techniques.
Of special importance is the definition of energy under non-sinusoidal conditions. Popular non-sinusoidal
power theories are evaluated and the approach of Czarnecki is shown to have an important deficiency in
practical power system applications. The Czarnecki three-phase power components are shown to be
questionable as to their physical significance. It is proposed that energy formulation should be carried out
in a transformed domain and it is demonstrated that the well-known Park current and voltage vectors
enable valid descriptions for energy phenomena in three wire three-phase power systems. A new
transform that transforms four wire three-phase quantities to three-dimensional space vectors of voltage
and current is shown to deserve further investigation towards implementation in compensation techniques
and tariff systems.
Knowledge on the relative contribution to the overall distortion of a specific source of distortion in a
power system requires the localisation thereof and a measurement technique. It is shown through time-domain
modelling that it is not possible to localise distortion sources through single-point measurements
in power systems in the presence of multiple harmonic distortion sources. This principle renders all
attempts to quantify power system distortion through single-point measurements invalid. The implication
is that penalisation of distorting customers by measuring their emission, will not be possible if all nodes
over the power system is not measured synchronously. Therefore, final proof to this principle is given
through the results obtained by measurements taken in a real-life power system.
The novel combination of a new power quality index and a distributed measurement system that does not
require accurate synchronisation in time is proposed as a practical approach in quantifying distortion
contribution of specific distortion sources and should be investigated further. It can aid towards managing
non-sinusoidal conditions in a power system through the implementation thereof in a self-regulating tariff
structure. === Thesis (Ph.D. (Electrical Engineering))--North-West University, Potchefstroom Campus, 2006.
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