Jovan Mikulović

Optimal Reactive Compensators in Power Systems Under Asymmetrical and Nonsinusoidal Conditions

Based on the condition for the minimum rms value of line currents, a method for improving the power factor in power systems under asymmetrical and nonsinusoidal conditions is presented. This paper offers straightforward and convenient formulations of active currents for the three-phase four-wire, three-phase three-wire, and single-phase systems. Owing to the transformation matrix introduced in this paper, the formulation of active currents is valid regardless of whether the voltages and currents are balanced or unbalanced and it permits any point of the system to be chosen for the voltage reference. Observing the constraints related to the reactive compensators, the line current minimization procedure is used for the determination of optimal compensating capacitances for the three-phase four-wire, three-phase three-wire, and single-phase systems. The optimal reactive compensators based on up to six capacitors are proposed. The definitions of power factors before and after compensation are introduced. The influence analysis of nonactive power compensation on harmonic distortion of line currents has been also performed. Experimental results are obtained to confirm the validity and applicability of the proposed compensation procedure.

A new reactive power definition based on the minimization of the load non-reactive currents

The paper surveys the reactive power definition for non-sinusoidal unbalanced poly-phase systems. Based on minimisation of non-reactive currents of the load, a new definition of reactive power is proposed. The simulation results confirm the validity and applicability of the proposed definitions for a variety of loads.

A new formulation of apparent power for nonsinusoidal unbalanced polyphase systems

The paper surveys the apparent power definition for nonsinusoidal unbalanced polyphase systems. Based on fact that zero-sequence voltages do not contribute to the instantaneous power, a new formulation of apparent power in terms of any voltage reference has been proposed.

Impact of cloudiness on direct and diffuse components of horizontal solar irradiation

One of the main tasks when planning a solar power plant is making a good resource analysis of the location of interest. In this paper, solar radiation data are aggregated by pyranometer which is used for measuring ten-minute values of solar irradiance on a horizontal surface during a whole year. Solar irradiance on a horizontal surface can be decomposed to direct and diffuse components. It is clear that cloudiness has a great impact on both direct and diffuse components of solar radiation. Based on one year solar irradiance measurement data, the sensitivity of direct and diffuse components to cloudiness has been analyzed. Cloudiness data used in the analysis are obtained from the standard hydro-meteorological measurements carried out by meteorological station. Based on the dependence of relative values of direct and diffuse horizontal irradiation on cloudiness and by using the calculated reference values of horizontal irradiation, a simple model for estimation of solar insolation is derived.

10.5937/zeint24-4934 = Analysis of technical-economic requirements for the construction of a solar power plant on the roof of the business building of the Electrical Engineering Institute 'Nikola Tesla'

У раду је приказана анализа техно-економских услова изградње соларне електране на крову пословне зграде Електротехничког института „Никола Теслаˮ у Београду. Извршен је прорачун ирадијације која пада на соларне панеле постављене на датој локацији у току ведрог дана, као и прорачун који је заснован на резултатима мерења хоризонталне ирадијације у Београду. Приказано је идејно решење распореда панела на крову зграде и њиховог повезивања на инверторе. Проверени су услови за прикључење електране на дистрибутивну мрежу и извршена је економска анализа пројекта.