1. Performance Enhancement of Grid Connected Multilevel Inverter Based Wind Energy Conversion System with LVRT Capability Using Optimized Type 2 ANFIS Based DVRCh. Sajan, P. Satish Kumar, Peter Virtič, 2024, izvirni znanstveni članek Opis: A Permanent Magnet Synchronous Generator (PMSG) based Wind Energy Conversion System (WECS) holds significant importance in the realm of Renewable Energy Sources (RES) for several reasons. The permanent magnets in the generator eliminate the need for a separate excitation system, leading to improved efficiency in power conversion. This makes PMSG-based WECS an effective and reliable source of wind energy electricity. The motivation behind the proposed conceptual framework stems from the need to overcome the limitations related to the integration of RES into the power grid, specifically focusing on voltage stability and Low Voltage Ride Through (LVRT) capability of PMSG based WECS. A Dynamic Voltage Restorer (DVR), empowered by an energy storage device, is used to mitigate voltage fluctuations and disturbances. The input DC voltage to the DVR is intricately regulated by a Type 2 Adaptive Neuro Fuzzy Inference System (ANFIS) Controller optimized using the Seagull algorithm, exhibiting intelligent adaptability to dynamic conditions. The rectified output from the WECS transforms an Isolated Flyback converter. Subsequently, a 31-Level Cascaded H-Bridge Multilevel Inverter (CHBMLI) along with a Proportional-Integral (PI) controller aids in generating high-quality AC output. By addressing challenges related to voltage stability and the ability to ride through low-voltage conditions, the proposed work contributes to enhanced grid stability. The use of advanced control techniques, including the Type 2 ANFIS Controller optimized by the Seagull algorithm, adds a layer of intelligent adaptability to changing environmental and grid conditions. A lower Total Harmonic Distortion (THD) Value of 1.29% is shown during the validation of the created system utilizing MATLAB/Simulink, assuring significant LVRT capabilities.
Ključne besede: Permanent Magnet Synchronous Generator (PMSG), Wind Energy Conversion System (WECS), Renewable Energy Sources (RES), Low Voltage Ride Through (LVRT), Type 2 Adaptive Neuro Fuzzy Inference System, 31-Level CHBMLI, Proportional-Integral (PI)
Objavljeno v DKUM: 06.11.2025; Ogledov: 0; Prenosov: 1
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2. Enhancing grid stability and low voltage ride through capability using type 2 fuzzy controlled dynamic voltage restorerCh. Sajan, P. Satish Kumar, Peter Virtič, 2024, izvirni znanstveni članek Opis: Introduction. The integration of Renewable Energy Sources (RESs), particularly Wind Energy Conversion Systems (WECS), is vital for reducing reliance on fossil fuels and addressing climate change. However, this transition poses challenges, including ensuring grid stability in the face of intermittent RESs. Compliance with grid codes is crucial, with a focus on Low Voltage Ride Through (LVRT) capability.
Problem. The intermittent nature of RESs, specifically in Permanent Magnet Synchronous Generator (PMSG) based WECS, presents challenges to grid stability during voltage dips.
Goal. To enhance voltage stability and LVRT capability in PMSG-based WECS by integrating a Dynamic Voltage Restorer (DVR) with an energy storage device. This involves regulating the input DC voltage to the DVR using a type 2 fuzzy controller, adapting intelligently to changing conditions.
Methodology. DVR, powered by an energy storage device, is strategically integrated with WECS. A type 2 fuzzy controller regulates the DC voltage to DVR. The rectified WECS output undergoes processing through an isolated flyback converter. A 31-level Cascaded H-Bridge Multilevel Inverter (CHBMLI) with PI control ensures high-quality AC output.
Results. The validation of developed system is executed using MATLAB/Simulink revealing a reduced Total Harmonic Distortion (THD) value of 1.8 %, ensuring significance in LVRT capability.
Originality. The strategic integration of DVR with PMSG-based WECS, addresses the LVRT challenges. The use of type 2 fuzzy controller for intelligent voltage regulation and a sophisticated multilevel inverter contributes to the uniqueness of proposed solution.
Practical value. The developed system provides benefits by ensuring reliable LVRT capability in PMSG-based WECS with reduced THD of 1.8 % indicating improved grid compatibility. References 26, tables 5, figures 20.
Ključne besede: permanent magnet synchronous generator, wind energy conversion systems, low voltage ride through, type 2 fuzzy controller, isolated flyback converter, 31-level cascaded H-bridge multilevel inverter, PI controller
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4. Developing an alternative calculation method for the smart readiness indicator based on genetic programming and linear regressionMitja Beras, Miran Brezočnik, Uroš Župerl, Miha Kovačič, 2025, izvirni znanstveni članek Opis: The European Union is planning to introduce a new tool for evaluating smart solutions in buildings—the Smart Readiness Indicator (SRI). As 54 energy efficiency categories must be evaluated, the triage process can be long and time-intensive. Altogether, 228 data points (or inputs) about the smartness of the buildings are required to complete the evaluation. The present paper proposes an alternative calculation method based on genetic programming (GP) for the calculation of Domains and linear regression (LR) for the calculation of Impact Factors and the total SRI score of the building. This novel calculation requires 20% (Domain ventilation and dynamic building envelope) to 75% (Domain cooling) fewer inputs than the original methodology. The present study evaluated 223 case study buildings, and 7 genetic programming models and 8 linear regression models were generated based on the results. The generated results are precise; the relative deviation from the experimental data for Domain scores (modelled with GP) ranged from 0.9% to 2.9%. The R2 for the LR models was 0.75 for most models (with two exceptions, with one with a value of 0.57 and the other with a value of 0.98). The developed method is scalable and could be used for preliminary and portfolio-level screening at early-stage assessments.
Ključne besede: SRI, modelling, genetic programming, linear regression, energy efficient buildings, smart buildings, optimisation
Objavljeno v DKUM: 03.11.2025; Ogledov: 0; Prenosov: 1
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5. Research on the modelling and analysis of the penetration of renewable sources and storage into electrical networksEva Simonič, Sebastijan Seme, Klemen Sredenšek, 2025, izvirni znanstveni članek Opis: To address the growing integration of renewable energy sources and storage systems into distribution networks, there is a need for effective tools that can assess the impact of these technologies on grid performance. This paper investigates the impact of integrating residential rooftop photovoltaic (PV) systems and battery energy storage systems (BESSs) into low-voltage (LV) distribution networks. A stochastic approach, using the Monte Carlo method, is applied to randomly place PV systems across the network, generating multiple scenarios for power flow simulations in MATLAB Simulink R2024b. The method incorporates real-world consumer load data and grid topology, representing a novel approach in simulating distribution network behaviour accurately. The novelty of this paper lies in its ability to combine stochastic PV placement with real-world load data, providing a more realistic representation of network conditions. The simulation results revealed that widespread PV deployment can lead to overvoltage issues, but the integration of BESSs alongside PV systems mitigates these problems significantly. The findings of this paper offer valuable insights for Distribution Network Operators, aiding in the development of strategies for optimal PV and BESS integration to enhance grid performance.
Ključne besede: photovoltaic system, battery energy storage system, low-voltage distribution network, Monte Carlo method, power flow
Objavljeno v DKUM: 03.11.2025; Ogledov: 0; Prenosov: 5
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6. Environmental pollution and economic activity : estimating the environmental Kuznets curve for a panel of countries worldwideDarja Boršič, Petar Todorčević, Nejc Fir, 2025, izvirni znanstveni članek Opis: This paper aims to assess the impact of certain economic factors on pollution for selected 112 countries worldwide. Due to data availability, carbon dioxide emissions in tonnes per capita were chosen as the dependent variable measuring pollution. Based on panel data and generalized moments method, the relationship between economic activity and environmental pollution was estimated. The results show that in the whole sample, as well as for two subsamples of developed and undeveloped countries, carbon dioxide emissions are statistically significantly affected by gross domestic product per capita, energy intensity and renewable energy consumption. The linear effect of economic activity positively effects the pollution, while the quadratic relationship is negative. Thus, the validity of inverted-U curve of the environmental Kuznets curve has been demonstrated. The estimated effect of economic activity measured by gross domestic product per capita on pollution does not differ in developed and undeveloped countries.
Ključne besede: environmental Kuznets curve, carbon dioxide emissions, renewable energy, industrialisation, urbanisation, economic development, cross-section analysis
Objavljeno v DKUM: 21.10.2025; Ogledov: 0; Prenosov: 1
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7. Experiences as heuristics for geothermal public perception : testing the correlation between thermal waters recreation and geothermal energy perceptionMaja Turnšek, Katja Kokot, 2025, izvirni znanstveni članek Opis: This research focuses on the question of how geothermal energy public perception is formed within a national context where news media do not pay attention to geothermal energy, and there is no active opposition to geothermal energy. The research builds on theoretical underpinnings of heuristics in energy perceptions and highlights the importance of physical experiences and associations as sources of experiential learning. Through a survey conducted among members of the general public in Slovenia, the role of thermal water recreation in shaping public perception of geothermal energy is empirically tested. The results show that, in this context, geothermal energy is highly positively assessed compared to hydro energy and nuclear energy, and that there is a correlation between frequency of thermal recreation and certain aspects of public perception of geothermal energy. The policy implications go beyond the simple recommendation of including tourism in public awareness campaigns but point to the specific vulnerability of energy acceptance in this context, where perceptions are formed based on “thinking fast”, and where the media and the public discourse on geothermal energy have not (yet) considered the potential risks and opposition to geothermal projects.
Ključne besede: geothermal energy, public perception, heuristic, experience design, tourism, nuclear energy, hydro energy
Objavljeno v DKUM: 14.10.2025; Ogledov: 0; Prenosov: 3
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8. Strategic integration of sustainability, circular economy, and blockchain in Slovenian urban governanceGorazd Justinek, 2025, izvirni znanstveni članek Opis: Slovenia has 12 urban municipalities, each with a sustainable development strategy aligned with the Agenda 2030 framework and valid through 2030. This paper examines how these strategies incorporate emerging technologies, particularly blockchain, and innovative sustainability concepts such as the circular economy. Achieving the goals of Agenda 2030, especially transitioning to a circular economy, requires doubling energy efficiency by 2030. While blockchain and the circular economy have often been studied separately, this research explores their intersection within the context of urban sustainability. The study applies qualitative content analysis to the official development strategies of all 12 urban municipalities. This analysis is complemented by semi-structured interviews with senior officials from the Ministry of the Environment, Climate and Energy, and the Vice Mayor of Ljubljana, providing institutional perspectives on strategic priorities and implementation logic. This is the first comprehensive analysis of how Slovenian urban municipalities address the interconnected themes of sustainability, circular economy, and blockchain technology. The findings contribute to academic discussions and offer practical recommendations to enhance innovation in urban sustainability planning
Ključne besede: blockchain, circular economy, energy efficiency, Agenda 2030, urban municipality
Objavljeno v DKUM: 02.10.2025; Ogledov: 0; Prenosov: 3
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9. Consumer protection in the electricity market in the European Union and Slovenia : vulnerable customers and emergency supplyNina Sotošek, Peter Virtič, 2025, izvirni znanstveni članek Opis: The article examines consumer protection in the electricity market, focusing on vulnerable customers and the right to emergency supply. At EU level, it outlines the development from the energy legislative packages to Directive (EU) 2019/944, which strengthens consumer rights and requires Member States to define and protect vulnerable groups. In Slovenia, these issues are regulated by Article 33 of the Electricity Supply Act (ZOEE), implemented through the System Operating Instructions (SONDSEE) and the Energy Agency’s act on criteria for ensuring emergency supply. The article applies normative and comparative legal analysis, reviews the Energy Agency’s Annual Reports, and analyzes case law. The findings reveal a gap between regulation and practice, as only one request for emergency supply was approved in Slovenia, in 2019. It proposes clearer criteria, simpler procedures, and more effective consumer information, particularly for vulnerable groups, to ensure the right to emergency supply is realized in practice.
Ključne besede: consumer protection, vulnerable customers, emergency supply, electricity market, ZOEE, Directive (EU) 2019/944, energy poverty, Energy Agency
Objavljeno v DKUM: 01.10.2025; Ogledov: 0; Prenosov: 5
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10. Assessment of harmonic distortion in school buildings equipped with grid-connected PV systemsFranjo Pranjić, 2025, strokovni članek Opis: The integration of photovoltaic systems into power grids can impact power quality, particularly concerning voltage and current harmonics. This study investigates the power quality of a photovoltaic system integrated into the electrical system of an educational facility, focusing on harmonic distortion in both voltage and current. Comprehensive measurements were conducted across three phases and analysed according to the EN 50160 and IEEE 519 Standards. The results demonstrated that, while the voltage quality meets EN 50160 requirements consistently, indicating stable voltage levels, the current measurements revealed significant harmonic distortion. Notably, Phase 2 exhibited Total Harmonic Distortion values substantially above the acceptable limits, with Phase 1 and Phase 3 also showing elevated Total Harmonic Distortion. To address these issues, the study recommends the implementation of advanced harmonic filters and optimisation of inverter technologies. These measures are crucial for enhancing power quality, and ensuring compliance with the industry Standards in high photovoltaic penetration scenarios.
Ključne besede: power quality analysis, grid-connected PV systems, EN 50160 standard, IEEE 519 Standard, IEC 61000 standard, voltage harmonics, current harmonics, harmonic distortion, renewable energy integration, compliance assessment
Objavljeno v DKUM: 01.10.2025; Ogledov: 0; Prenosov: 0
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