CJEE: Volume 12, number 1, 2018

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Carpathian Journal of Electrical Engineering

Volume 12, Number 1 / 2018

Published papers:

The Reduction of Total Harmonic Distorsion for the Multilevel Converter Using Genetic Algorithms Optimization Method

  • Horatiu Dacian LASLO1Traian VARODI21SC Electroplus SRL Cluj-Napoca, 2Technical University of Cluj-Napoca,  Această adresă de e-mail este protejată de spamboţi; aveţi nevoie de activarea JavaScript-ului pentru a o vizualiza
  • Keywords: distorsion, multilevel converter, algorithms
  • Abstract: Electricity DC voltage- AC voltage conversion generated from certain renewable energy sources such as photovoltaic panels should be made with quality factors imposed by the present standards. In the case of multilevel converters the achievement of reasonable distortion factor is realized by optimizing the targeted waveform using Newton Raphson method. This paper presents an optimization solution based on genetic algorithm. Voltage waveforms obtained by this technique and the total harmonic distortion degree of reduction are presented by comparing the results obtained from supplying a consumer with a voltage generated in classical way through DC-AC conversion, using multilevel converter.

Real-Time Transient Stability Status Prediction Scheme and Comparative Analysis of the Performance of SVM, MLPNN and RBFNN 

  • Emmanuel Asuming FRIMPONG1, Philip Yaw OKYERE1Johnson ASUMADU2, 1Kwame Nkrumah University of Science and Technology, Kumasi, Ghana, 2Western Michigan University, Kalamazoo, Michigan, USA,  Această adresă de e-mail este protejată de spamboţi; aveţi nevoie de activarea JavaScript-ului pentru a o vizualiza
  • Keywords: neural networks, out-of-step, support vector machine, transient stability
  • Abstract: This paper presents a simple and effective technique for real-time prediction of transient stability status following a large disturbance and compares the performance of three artificial intelligence (AI) techniques commonly employed as decision making tools. The (AI) techniques compared are support vector machine (SVM), multilayer perceptron neural network (MLPNN), and radial basis function neural network (RBFNN). The stability status prediction scheme samples rotor angles of all system generators and extracts the absolute value of the first sampled rotor angle value of each generator. The extracted absolute rotor angle value of all generators are summed and fed as input to a decision tool. The scheme was tested using simulations carried out on the IEEE 39-bus test system. One hundred percent prediction accuracy was obtained when SVM and MLPNN were each employed as decision tools. The use of the RBFNN as decision tool resulted in only sixty-three percent prediction accuracy.

Fragaria Daltoniana Algorithm for Solving Optimal Reactive Power Dispatch Problem

Closed Form Formulas for ELF Inductive Coupling between Finite Length Wires with Earth Return

  • Giovanni LUCCASIRTI S.p.A, Milano, Italy,  Această adresă de e-mail este protejată de spamboţi; aveţi nevoie de activarea JavaScript-ului pentru a o vizualiza
  • Keywords: electromagnetic interference, electromagnetic compatibility, electromagnetic coupling
  • Abstract: This paper deals with the evaluation of the inductive coupling between an overhead finite length wire circuit and a buried wire circuit, both with earth return, in the range of Extremely Low Frequencies (ELF). In particular, the attention is focused on the key parameter for this kind of problems i.e. the per unit length (p.u.l.) mutual impedance between the two circuits. Starting from the exact formula involving a Sommerfeld’s integral, two new approximated analytical formulas, having different levels of approximation, are derived; the advantage of these formulas is that, in such a way, the p.u.l. mutual impedance is expressed only by means of elementary functions so avoiding numerical calculations of the Sommerfeld’s integral. Finally, a comparison between the two proposed formulas is made.

Electricity Conservation and Safety Awareness Among Senior High School Students
  • Emmanuel Asuming FRIMPONG, ElvisTWUMASI, Department of Electrical and Electronic Engineering, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana,  Această adresă de e-mail este protejată de spamboţi; aveţi nevoie de activarea JavaScript-ului pentru a o vizualiza , Această adresă de e-mail este protejată de spamboţi; aveţi nevoie de activarea JavaScript-ului pentru a o vizualiza
  • Keywords: energy conservation, energy efficiency, electric safety
  • Abstract: Awareness of conservation and safety issues regarding electrical energy use among students is critical. This study has determined the level of electricity conservation and safety awareness among senior high school students in the Ashanti Region of Ghana. The study was carried out through the administration of questionnaires to eight hundred and eighty-three students in five selected schools in the study region. The study assessed awareness levels based on gender, programme of study and academic study level. The questionnaires were developed to establish student’s knowledge of specific energy conservation practices relating to various consumer appliances, their motivation or otherwise to support institutional efforts to reduce energy consumption as well as their awareness of specific issues regarding electric shocks and electric fires. Analysis of the administered questionnaires point to the fact that a very high percentage of the students in all the three categories considered are aware of most of the issues presented to them. Also, a high percentage of them are inclined towards factors that motivate energy savings. Of the categories evaluated, females, students in the first level of study, and those studying Home Economics had the highest average awareness levels. The findings of this study will be very useful for educational campaigns concerning electricity use.

Optimizing the Use of Green Energies, an Application to Crop Irrigation

  • Toufik SEBBAGH1, Ridha KELAIAIA1, Assia ABDELOUAHED2, and Abdelouahab ZAATRI31LGMM Laboratory, Université 20 Aout 1955 - Skikda, Algeria, 2Department of Civil Engineering, Université 20 Aout 1955 - Skikda, Algeria, 3University of Constantine 1, Constantine, Algeria,  Această adresă de e-mail este protejată de spamboţi; aveţi nevoie de activarea JavaScript-ului pentru a o vizualiza
  • Keywords: optimization, irrigation, renewable energy 
  • Abstract: This paper assesses the optimal farmland that can be irrigated by a predetermined renewable energy system. The optimal irrigated surface from an agriculture area, cultivated by potatoes and tomatoes and powered by a PV system is studied. Two scenarios are discussed: the constraints applied to the first scenario is the limited surface of the agricultural area. While in the second scenario, the surface cultivated with tomatoes must be at least ¼ the surface cultivated with potatoes. Linear programming based on the Simplex algorithm is used to solve the optimization problem. The obtained results show that for the specified cultivating area, and for 10 panels at hand, an optimal surface of about 5.6 ha and 4.7 ha for the first scenario and the second scenario, respectively can be satisfied.

A Modified Virtual Space Vector Modulation Technique for Z-source NPC Inverters

  • Francis EFFAH1, Philip OKYERE1, Patrick WHEELER2, Alan WATSON2, Jon CLARE21Kwame Nkrumah University of Scince and Technology, Kumasi, Ghana2University of Nottingham, Nottingham, UK,  Această adresă de e-mail este protejată de spamboţi; aveţi nevoie de activarea JavaScript-ului pentru a o vizualiza
  • Keywords: neutral point, voltage buck-boost, modulation, impedance network 
  • Abstract: A modified virtual space vector modulation approach for the control of a Z-source neutral point clamped inverter is presented in this paper. This approach works perfectly for the traditional neutral point clamped inverter. In this paper, the effectiveness of the virtual space vector modulation technique in balancing the input capacitor voltages of the Z-source NPC inverter with no low-frequency oscillations superimposed in addition to voltage buck-boost capability is demonstrated through simulations in SABER®. A prototype converter is used to capture experimental results for validation.

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