Abstract This paper presents a new approach for uncertainty determination of the electric field intensity and magnetic flux density calculation in the vicinity of overhead transmission lines. The ...proposed method is based on the law of propagation of uncertainty as defined in the Guide to the expression of Uncertainty in Measurement. A mathematical model is developed for determining the electric field intensity and magnetic flux density calculation uncertainty based on the Charge simulation method and method based on Biot – Savart law, respectively. The verification of the proposed method was performed by estimating the uncertainty of the electric field and magnetic flux density calculations for four single circuit and two double circuit high-voltage overhead transmission lines. The analysis of the obtained results demonstrates that the proposed method can be successfully used to determine the uncertainty of electric field intensity and magnetic flux density calculations in the vicinity of overhead transmission lines.
In this paper, a novel method for the magnetic flux density estimation in the vicinity of multi-circuit overhead transmission lines is proposed. The proposed method is based on a fully connected ...feed-forward artificial neural network model that is trained to estimate the magnetic flux density vector components for a range of single-circuit overhead transmission lines. The proposed algorithm is able to simplify estimation process in instances when there are two or more geometrically identical circuits present in the multi-circuit overhead transmission line. In such instances, artificial neural network model is employed to estimate the magnetic flux density distribution over a considered lateral profile for only one of such circuits. The magnetic flux density estimates of the other geometrically identical circuits are derived from these results. The proposed methodology defines the resultant magnetic flux density for the multi-circuit overhead transmission line in terms of the contributions made by individual circuits. The application of the proposed magnetic flux density estimation method is demonstrated on several multi-circuit configurations of overhead transmission lines. The performance of the proposed method is compared with the Biot-Savart law based method calculation results as well as with field measurement results.
In this paper, Huang’s Empirical Mode Decomposition approach is proposed for df/dt and active power imbalance in power system estimation. Applied approach implies availability of synchronized phasor ...measurement units. In addition to the successful applications in the analysis of nonstationary dynamic behavior of power system, identifications and analyses of low-frequency electromechanical oscillations and signals denoising, this approach also enables direct estimation of rate of change of a weighted average frequency (frequency of the center of inertia), as well as assessment of the overall imbalance in the power system. This demonstration is performed using computer simulation testing on the 39 Bus New England System and Western System Coordinating Council 118 bus test systems in the DigSILENT PowerFactory power system analysis software package. To validate the proposed approach the actual frequency information are used. Empirical Mode Decomposition approach is compared with Discrete Wavelet Transform, Method of Least Squares and the results from the DigSILENT PowerFactory. Also, performance of the empirical mode decomposition are compared with performances of the multivariate empirical mode decomposition and noise assisted multivariate empirical mode decomposition on both, simulated signals and field measurements. Applied approach is implemented in the MATLAB environment and results show very high accuracy.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The use of renewable energy sources increases the energy self-sustainability of cities, enabling citizens to reduce energy costs, which results in an increase in their standard of living. However, ...solar energy penetration in Bosnia and Herzegovina, and its capital Sarajevo, is not in line with the possibilities. Furthermore, the Sarajevo Canton is extremely polluted during the winter months because of the use of unacceptable heating fuel. The aim of this paper is to introduce photovoltaic power systems use in heating electrification system. In this paper AQI is calculated based on historical data and the hybrid model EMD-SARIMA for air pollution and a solar production forecast is presented. The methodology was tested in the Sarajevo Canton, taking into account 35,000 households. In order to ensure clean air, renewable electric energy use for household heating should be implemented. The widespread use of inefficient individual heating systems characterized by inefficient and expensive use of firewood and the use of coal in individual furnaces in populated areas are the main problems of internal and urban air pollution in Sarajevo Canton. In order to reduce energy poverty in Sarajevo Canton, the use of a floating photovoltaic power plant located on Lake Jablanica with a capacity of 30 MW and the solar prosumers with capacity of 115 MW to provide the 196 GWh necessary for heating electrification of 35,000 households is implemented in this paper. Finally, based on correlation between AQI forecast and solar production it was calculated that the values of the AQI, considering the application of solar energy during 150 days (five months) in one heating season, have significantly decreased. Also renewable energy sources have a very important role in reducing carbon dioxide (CO2) emissions into the atmosphere and reducing urban pollution. With this approach, households would be heated by renewable electricity, which would make Sarajevo a cleaner, smarter city.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
The decrease in overall inertia in power systems due to the shift from synchronous generator production to renewable energy sources (RESs) presents a significant challenge. This transition affects ...the system’s stable frequency response, making it highly sensitive to imbalances between production and consumption, particularly during large disturbances. To address this issue, this paper introduces a novel approach using Multivariate Empirical Mode Decomposition (MEMD) for the accurate estimation of power system inertia. This approach involves applying MEMD, a complex signal processing technique, to power system frequency signals. The study utilizes PMU (Phasor Measurement Unit) data and simulated disturbances in the IEEE 39 bus test system to conduct this analysis. MEMD offers substantial advantages in analyzing multivariate data and frequency signals during disturbances, providing accurate estimations of system inertia. This approach enhances the understanding of power system dynamics in the context of renewable energy integration. However, the complexity of this methodology and the requirement for precise data collection are challenges that need to be addressed. The results from this approach show high accuracy in estimating the rate of change of frequency (RoCoF) and system inertia, with minimal deviation from actual values. The findings highlight the significant impact of renewable energy integration on system inertia and emphasize the necessity of accurate inertia estimation in modern power systems.
This paper introduces and compares the various techniques for identification and analysis of low frequency oscillations in a power system. Inter-area electromechanical oscillations are the focus of ...this paper. After multiresolution decomposition of characteristic signals, physical characteristics of system oscillations in signal components are identified and presented using the Fourier transform, Prony method, Matrix Pencil Analysis Method, S-transform, Global Wavelet Spectrum and Hilbert Huang transform (Hilbert Marginal Spectrum) in time-frequency domain representation. The analyses were performed on real frequency signals obtained from FNET GridEye system during the earthquake that triggered the shutdown of the North Anna Nuclear Generating Station in the east coast of the United States. In addition, according to the obtained results the proposed methods have proven to be reliable for identification of the model parameters of low-frequency oscillation in power systems. The relevant analyses are carried out in MATLAB coding environment.
This paper considers the method for the calculation of magnetic flux density in the vicinity of overhead distribution lines which takes into account the higher current harmonics. This method is based ...on the Biot–Savart law and the complex image method. The considered method calculates the values of the magnetic flux density for each harmonic component of the current separately at all points of interest (usually lateral profile). In this way, it is possible to determine the contributions of individual harmonic components of the current intensity to the total value of magnetic flux density. Based on the contributions of individual harmonic components, the total (resultant) value of the magnetic flux density at points of interest is determined. Validation of the computational method is carried out by comparison of the results obtained by the considered calculation method with measurement results. Furthermore, the application of the calculation method was demonstrated by calculating magnetic flux density harmonics in the vicinity of two overhead distribution lines of typical phase conductor arrangements.
Modern power systems are a very complex dynamical system spreading over a large geographical area. They indicate very complex phenomena in some parts as well as in the whole interconnected power ...system. In large and complex systems, there are coherent groups of generators. A group of generators in one area swings against a group of generators in another area. In this paper, using the Huang's Empirical Mode Decomposition (EMD) signals of the rotor-angle oscillations are separated into several Intrinsic Mode Functions (IMFs) and, thereafter, the correlations between IMFs are applied as a coherency measure and criterion for identification of coherent- generator groups in a power system. The applied approach is analysed for the Kundur two area-four machines test system and New England (NE) bus 39 test system. A comparison between the results of NE bus 39 test system with those of other researches shows a high degree of similarity.
Introduction
The electroencephalography (EEG) is a graphical representation of the electrical activity of the brain, which is recorded through electrodes placed on the scalp and is used as the method ...of choice for the diagnosis of epilepsy. The appropriate assessment of this report despite valid entries now is able to give a very small number of doctors in this field. Misdiagnosis of epilepsy leads to multiple negative consequences. Using the wavelet transformation can be identified all interictal spikes in this report, which is a big advantage in interpretciji compared with the standard method. The wavelet transform signal is represented with wavelet functions that are generated from the basic functions with the procedures of scaling and translation. This method in the analysis of EEG recording is faster, clearer, more precise, and possibly a cheaper method. This study was done in the Department of Neuropediatricians of the Pediatric Clinic of the University Clinical Centre in Sarajevo, where we analyzed the EEG signals in patients with epilepsy using wavelet transform. The respondents were people aged 1 to 18 years with a diagnosis of epilepsy. These results were verified with conventional method.
Aim
Using the wavelet transform greatly contributes to the correct and objective interpretation of the EEG records.
Materials and Methods
We presented the mathematical model of the Wavelet transform analysis of EEG records of people diagnosed with epilepsy.
Keywords
electroencephalography; wavelet transform; analysis; epilepsy; interictal spikes
This paper deals with algorithm for placement and sizing of the shunt capacitor banks in distribution networks of radial structure. In this paper algorithm for optimal placement and sizing of shunt ...capacitor banks is based on load flow calculation algorithm and integer genetic algorithm. Firstly, paper describes the problem of optimal placement and sizing of the shunt capacitor banks with constrains. Also, paper describes algorithm for the calculation of the load flow in the radial distribution networks. Used integer genetic algorithm is also presented. Proposed algorithm was verified on the IEEE 34 bus test distribution network. Finally, practical application of the proposed algorithm was demonstrated on one real 10 kV distribution network in Bosnia & Herzegovina.
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