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The earth grounding (EGR) computation model contained in normative acts has multiple nonlinearities and functions with implicit definitions. In addition, through the values indicated for the utilization coefficients, the designers are oriented towards relatively large distances between electrodes and no optimal criteria are defined. In earlier works, the authors have realized nomograms in order to...
Based on previous research experience proved by simulated and experimental results a comparative discussion about advantages and disadvantages of using Vector Control or Direct Torque Control for PM-SM drives is presented.
The output voltage analysis of PWM inverter, from the photovoltaic (PV) power plant, represents the first of the objectives of this research. On the one hand, a real voltage wave is analyzed, taken by oscillography and on the other hand two waveforms are identified, alternative step type, by multiplying and their composing, any form of output voltage can be obtained from PWM inverters. The two signals...
In previous papers, the authors have resumed the earth grounding dimensioning with the intend to propose optimum criteria and to simplifying the design procedure. Five general characteristic sizes for the earth grounding have been proposed that may be in as many objective functions. Of these, the footprint area, the total metallic mass and the earth grounding volume have already been approached with...
Properly sizing of earth grounding is a current issue of designers, because successive iterations required, which are determined by the nonlinearity calculating relations on the one hand and their complex structure, on the other hand. Continuing sizing methods improvement of the earth grounding, the paper applies three optimization criteria targeting the footprint minimizing, the total volume and...
The short time overvoltages and the voltage impulses represent Power Quality disturbances, with significant economic consequences, both for end-users and for suppliers also. Currently, there are defined too few sizes characteristic of these ones, insufficient for a correct assessment of their consequences. A new series of characteristic sizes both for short time overvoltages and voltage impulses are...
The design of earth grounding at rated values corresponding to the role to be accomplished is relatively laborious and there are no highlighted optimum criteria giving the justification for the chosen solution. The vertical earth grounding calculus is restructured in this paper, realizing sizing nomograms which include all characteristic sizes, the final goal being the determination of the electrodes...
Voltage dips represent a Power Quality disturbance with the most significant economical consequences. However, too few of their characteristic sizes are defined, such as voltage sags amplitude and frequency. A new series of characteristic sizes for the voltage sags are justified presented in this paper, forming together with the already known a complete indicators family, for this aspect of Power...
Highlighting the inadequacies in terms of flicker indicators and proposals for overcoming them are the paper principal aims. High level sensitivity of the visual perception at luminance fluctuations as well as at flicker requires increased attention to this phenomenon, and also to the causes that produce them, careful highlighted in the paper.
To know the electrical power losses of an electrical network from an established perimeter and to adopt some measures in order to obtain their decrease represent very important problems in the electrical networks exploitation and maintenance. Thus, this paper aims to realize the model of the medium voltage (MV) network belonging to the electrical station Centre from the urban area of Cluj-Napoca in...
This paper is concerned with robust vector control of a permanent magnet synchronous motor (PM-SM) using a fix-point DSP based computing architecture. Speed control systems are analyzed for different operation conditions. A hardware architecture was developed based on a TMS320C5x fixed-point processor, a PWM control unit realized in FPGA technology, an interfacing unit to the incremental encoder and...
The flaring phenomenon or flicker is framed with no less than three indicators for which there are normalized values. The methodologies for determining indicators as flicker dose and severity as well as the voltage fluctuations limits use graphic functions, experimentally determined. A LabVIEW original program is used in order to identify the optimal analytical expressions for graphic or tabular functions...
In the domain of electrical installations, as in many other areas where theoretical researches are intertwined with the experimental ones, there are some dependencies that are known and used in the initial given form, which can be graphically or tabular. Correction of the demand coefficients based on the equivalent number of receivers, the protection characteristics of the fuses and the photometric...
Both suppliers and end-users are more interested in knowing the power quality (PQ) level through their common network. Unfortunately, there are no clear experimental methods and especially interpretable for all PQ aspects. This is also the case of the slow voltage variations about which it is theoretically known that they include variations with periods between (5 min+24 h), so practically the voltage...
The power quality (PQ) indicators, related to slow voltage variations, are expressed usually both absolute and relative values. Consequently, the paper presents the complete family of slow voltage variations indicators in expression of absolute, relative and percentage. The necessity of an expressive analysis of voltage variations led to idea of the voltage wave decomposition in actions and harmonics...
Luminaires new catalogues highlight permanent changes in their technology and equipment, determining deep implications on the distribution of the emitted luminous flux. Using the index of correlation between the indoor luminaires photometric curves (Philips) and those defined through the functions from the BZ classification, indicates that some of the first category are not included among those from...
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