On separating customer and supply side harmonic contributions at the pcc based on new notions suggested to power theory development

Excessive use of nonlinear loads connected to electric power systems distorts the AC power current, and consequently the AC voltage drop. Thereby resulting in the flow of harmonic currents in the system. This can introduce many problems through out the system. If such problems are unavoidable, then remedy or mitigation and cost of such action should be properly accounted for as fairly as possible. Due to this reason, it is important to determine precisely the quantity and direction of energy and power for each harmonic order. This will be very useful while constructing energy billing and rate structure.This thesis concerns with this matter, which is called reverse harmonic study. It introduces a new method to determine the attributes for each harmonic order at the point of common coupling (PCC) between the supplier and the consumer.Depending on the premise that harmonics cause power flow in power systems, just as fundamental frequency does, the thesis analytically introduces a new approach to develop the power theory. The purpose of this approach is to determine an accurate, fair, practical method for measuring the harmonic power components and energy transfer.There is consensus that the present definitions used to evaluate the flow of energy and power in electric networks are not adequate for conducting studies when non-sinusoidal voltage or current are present. For that reason the thesis suggests a new notion in power theory for periodic current and voltage waveforms. The idea of this notion has been inspired from the concept of instantaneous power. This term has been defined for convenience in representing the energy content of a system, since it satisfies the law of conservation of energy. By this new approach we have analytically introduced definitions and formulas that determine precisely proper instantaneous power components in ac power systems under sinusoidal and non-sinusoidal conditions. The rapid progression of digital sampling technology in power metering now has introduced modern technical possibilities for measuring any power component if the formulas for its calculation have been found. The suggested notion is a trial to determine those formulas in order to have the opportunity of such modern meters advantages. According to the new notion suggested, the wave shape of the total instantaneous power consists of two parts:1.Constant value represents the summation of all the harmonic average active (true) powers considering its sign or direction.2.Sinusoidal power components (named phasor, distortion and fictitious) for each harmonic order Concerning the total energy flow, it is proven that the true energy that totally transfers to (or from) the system is the energy which belongs to the average true power only i.e. active power produced from the voltage and current of the same harmonic order. All other kinds of energy are fluctuating sinusoidally and give a zero average value i.e. the net transfer of energy belongs to sinusoidal powers components is nil.Concerning the harmonic power flow, it is proven that the aggregate sinusoidal nonactive part of the nth harmonic instantaneous power (named fictitious power) is a vector sum of active and reactive powers only. Accordingly, it is possible to compare the magnitude and direction of both the active and reactive power components resulting from the fictitious power, for each harmonic order, with respect to reference direction of the power generated from the fundamental voltage and current. Thus, we can determine who is the source of harmonic power for each harmonic order (the supply side or the customer side).