The transition process from fossil fuels to environmentally friendly renewable energy sources carries the risk of creating new environmental damages. Photovoltaic technology represents one of the alternatives with the least risk of harmful environmental impact. However, this technology has two important drawbacks: the significant land occupation for the installation of PV systems and the uncontrollability of production. By constructing floating photovoltaic plants on hydroelectric reservoirs, both of these problems can be reduced to an acceptable level. Some artificial reservoirs, originally built for hydroelectric power plants, have acquired a significant secondary function as recreational areas and fish breeding sites. Therefore, there is justified resistance from the local community to change the existing appearance and purpose of such reservoirs. This paper proposes a completely new concept of integrating the interests of the local community into such objects. In addition to preserving existing uses, the concept also offers new features. This can make the entire system environmentally friendly and sustainable. This paper details the technology behind the construction of floating photovoltaic power plants on artificial reservoirs and emphasizes their various advantages. These benefits include the non-utilization of cultivable land, the ease of assembly and construction, integration into existing power grids, and the potential to address electricity storage issues. For instance, Buško Lake, covering an area of 55.8 km2, may host 2.93 km2 of installed floating photovoltaic (FPV) facilities, enabling a total installed capacity of 240 MW. With an average of 5.5 h of daily sunshine, this totals 2007 annual hours, equivalent to a 55 MW thermal power plant. An analysis showed that, with losses of 18.2%, the average annual production stands at 302 GWh, translating to an annual production value of 18 million € at 60 €/MWh. The integration of this production into an existing hydroelectric power plant featuring an artificial reservoir might boost its output by 91%. The available transmission line capacity of 237 MW is shared between the hydroelectric power plant (HPP) and FPV; hence during the FPV maximum power generation time, the HPP halts its production. HPP Orlovac operates a small number of hours annually at full capacity (1489 h); therefore in combination with the FPV, this number can be increased to 2852 h. This integration maintains the lake’s functions in tourism and fishing while expanding its capabilities without environmental harm.

This research delves into the crucial role of solar energy, particularly photovoltaic (PV) conversion, in the global shift towards renewable sources. Focusing on the stochastic nature of PV power plants, the study emphasizes fault ride-through operations and their repercussions on electrical power systems. A detailed modeling approach is employed using Electromagnetic Transient Program (EMTP) software to simulate a large-scale PV power plant connected to a high-voltage transmission network. The analysis encompasses various fault scenarios, shedding light on the resilience of PV systems and their broader impacts during faults. This investigation enhances the understanding of PV dynamics in fault conditions, providing valuable insights for sustainable energy systems.

Large-scale incorporation of new energy generation units based on renewable sources, such as wind and photovoltaic power, drastically alters the structure of the power system. Because of the intermittent nature of these sources, switching in grids (connection and disconnection) occurs much more frequently than with conventional sources. As a result, the power system will inevitably experience a large number of transients, which raises questions about the stability of the system and the quality of the electrical energy. Therefore, measuring various types of transients in power system is crucial for stability, power quality, fault analysis, protection design, and insulation design. Transient recorders that are currently used are generally expensive and only suitable for particular locations in power systems. The number of installed transient recorders is insufficient for a comprehensive analysis of problems that may occur. Hence, it is important to have inexpensive and efficient transient recorders that can be installed at multiple points in the power system on various types of objects. It is also essential to have a transient record database with open access, which can be used by researchers to develop new analysis techniques based on artificial intelligence. This paper proposes an inexpensive measurement and acquisition system designed to record transient phenomena on different objects within the power system. The system is designed to use autonomous power, a standardized data acquisition module, a low-budget system for transmitting recorded transient events to the server via mobile network, and a sensor system adapted to the object where transients are recorded. The proposed system is designed to be used for all types of objects in the power system where transients may occur, such as power lines, transmission towers, surge arresters, and transformers. All components of the system are described, and the system is tested under laboratory conditions. The modular nature of the system allows customization to the specifics of the location in power system by choosing appropriate components. The calibration method of the custom designed Rogowski coil is described. The cost analysis of the proposed system and power consumption analysis are performed. The results show that the system’s performance meets application requirements at a low cost.

At the beginning of the 21st century, environmental issues became leaders in all areas of human activity without competition. All other essential topics: health, food, energy, water, and air, are predominantly determined by environmental problems. Climate change is a result of excessive CO2 emissions due to the greenhouse effect, air pollution as a result of emissions of harmful substances by thermal power plants, chemical plants, heating boilers, individual furnaces, means of transport; pollution of drinking water, pollution and devastation of arable land, destruction of forests, pollution of rivers due to inadequate wastewater treatment, etc. are problems that require a radical change in man's attitude towards the environment, which leads to the need to reconsider and change the current way of doing business. The paper analyzes the impact of scientific achievements in electrical engineering on the accelerated industrial growth that has led to today's environmental problems. Industrial development is explored in phases (Industry 1.0, Industry 2.0, Industry 3.0, Industry 4.0) regarding the impact of radical changes in doing business. Since we are now in phase 4, the dominant topics are energy transition, energy efficiency, renewable energy sources, recycling, innovation, electric vehicles, networking, Internet of Things (IoT), artificial intelligence, and 5G. Although all the above topics are multidisciplinary, a significant share of electrical engineering is clear. Existing plans and programs in electrical engineering, whether based on the traditional model of education or in the process of innovation, are adapted to new technological trends. As a rule, little or no importance is attached to environmental issues. As one of the answers to the mentioned problem at the Faculty of Electrical Engineering, University of Sarajevo, a new course, “Sustainable Development” was included. The paper briefly describes the content of this course.

Lightning parameters are needed in different engineering applications. For the prediction of the severity of transient voltages in power systems, an accurate knowledge of the parameters of lightning currents is essential. All relevant standards and technical brochures recommend that lightning characteristics should be classified according to geographical regions instead of assuming that these characteristics are globally uniform. Many engineers and scientists suggest that better methods for lightning current measurements and analyses need to be developed. A system for direct lightning current measurements installed on Mount Lovćen is described in this paper. Observed data were analyzed, and statistical data on parameters that are of interest for engineering applications were obtained, as well as correlations between various lightning parameters. Furthermore, a novel approach for classifying and analyzing lightning data from direct measurements based on empirical mode decomposition (EMD) is proposed. Matlab was used as a tool for signal processing and statistical analysis. The methodology implemented in this work opens possibilities for automated analysis of large data sets and expressing lightning parameters in probabilistic terms from the data measured on site.

This paper analyzes the problem of DC cable selection in photovoltaic (PV) plants. PV plants can have tens of kilometres of one-way cables that are important parts of the system. The currents flowing through these cables can reach values of several hundred amps. Losses incurred on DC cables are up to 1%, which can be significant when measuring power loss during the operating period. Reduction of these losses can be achieved by increasing the cross-section of the cable. The paper describes the requirements set by the standards for selecting cable cross-sections. An analytical criterion function that connects electricity losses and cable crosssection were deduced. This function depends on several parameters such as electricity price, cable price, the average number of sunny hours per year, average amount of electricity through cable, interest rate, loan repayment period, and plant operation period. Several cases with the analysis of the obtained results are presented.

The development of Floating Solar Photovoltaic (FPV) systems is a sign of a promising future in the Renewable Energy field. Numerous solar modules and inverters are mounted on large-scale floating platforms. It is important to design the system so that the inverter operates in its optimum range most of the time. In order to achieve this goal on the DC side, serial and parallel connections of solar modules are used. As a result, the cabling of the PV array architecture is an important issue. Modern electrical installation design requires reducing costs in cabling materials, equipment installation, and maintenance. The reduction of losses and the amount of time required to complete the design are also significant. Therefore, the main topic of this paper is DC cabling in large-scale FPV power plants (>1 MV). The serial-parallel (SP) connection scheme of solar modules and the percentage of power loss in DC cables are considered. Furthermore, a general method for determining cable lengths for FPV power plants is defined. The temperature influence on losses in DC cables is analyzed. A new method for determining the current at the maximum power point (MPP) as a function of temperature is proposed. A case study is conducted using a hypothetical 3 MW FPV power plant, and the obtained results are presented and analyzed.

The paper analyzes the problem of the construction of utility-scale solar photovoltaic power plants (US-PV). Two main problems of this construction are: occupying usable areas and the connection and integration of the power plant into the electricity system. The construction of US-PV power plants on water accumulations of existing hydro power plants was analyzed, as one of the solutions to these problems. The Jablanica Lake was taken as an example. Jablanica Lake is an artificial accumulation lake on the river Neretva with an area of 13 km2 within the hydroelectric power plant (HPP) Jablanica with 180 MW of installed power. It was shown that on a surface of less than 3% of the total area of the accumulation of HPP Jablanica, there could be built a floating photovoltaic (PV) plant with a power of 30 MW. This power would add another generator of 30 MW to HPP Jablanica, which would increase the current number of the 6 generators to 7. This would enable significantly better exploitation of the Neretva and Rama river basins, and increase production in the summer period with a decrease in lake level oscillations. Suitable locations for the installation of floating solar power plant were analyzed. Locations are selected on the basis of requirements for the preservation of existing lake functions, and provide the possibility of installing a 3 MW power plant. 10 of these plants, connected by a 20 kV power grid, represent one US-PV 30 MW plant, which at one point connects to the transmission network of 220 kV. The specifications of one 3 MW power plant are given in terms of the required area, number of modules and number of inverters. A preliminary techno-economic analysis of the total plant was carried out. In this analysis, the possible production, the indicative price of the plant, and the price of the produced kWh of electricity are calculated.

The paper describes an implementation of a low-cost electrochemical impedance spectroscope using a sound card on a computer. The main parts of the system are: PC's sound card used for signal output and data acquisition, a current source, two measurement channels, software module for battery parameter estimation. The sinusoidal signal with required amplitude and frequency is generated from the MATLAB and using the D/A converter of the sound card. The current source is implemented as a class AB amplifier with a PI regulator. Measurement channels are designed to prepare battery response signals for the A/D conversion. The implementation allows utilizing different algorithms for parameters estimation. The system performance is demonstrated when used to estimate the parameters of a Lead-Acid battery, test results are presented and discussed.

In the paper, realized simulator for testing parameters estimation of the power system was described. Simulator allows definition of the test conditions like amplitude and phase, activity of decreasing direct component, variation of number of samples, variation of harmonic components, and change of frequency of the basic harmonic. The test criterion takes the error of the estimated value in relation to the default value and then time of convergence of the estimated value. As an illustration of algorithm functioning, the time format of the input signal and the timing response of the estimated amplitude and phase of signals are shown. In the simulator, algorithms for amplitude and phase estimation are implemented. For amplitude estimation, algorithms that were implemented: algorithm based on the Fourier bandwidth filter and algorithm based on the least squares method. For phase estimation, algorithms that were implemented: zero crossing algorithm and algorithm based on the Fourier bandwidth filter. All of the implemented algorithms are described and given with their mathematical models. Simulator was made in Matlab and can be expanded with addition of the noise, implementation of other algorithms, development and testing of new algorithms. For the demonstration of the usability of the simulator, results that were obtained by testing are shown.

This paper describes the current state of photovoltaic plants (PV) in Bosnia and Herzegovina (B&H). It describes the ongoing trends in this domain and the ongoing legislation. It gives a certain insight of the future development in this domain. The first PV plant in B&H was built in 2012. Since then 180 PV plants were built and connected to the power grid containing installed capacity of 18MW. This makes 0.37% of installed capacity in B&H. Because of these particular reasons B&H must, with the utmost seriousness, begin implementing projects of construction in the field of renewable energy and other forms of green energy. When considering renewable energy, solar energy it far most impressive and promising area of investments. This paper has analyzed the potential that B&H has in the construction of PV plants. Four areas of interest were analyzed: the roof tops of apartment buildings, certain protective parts around the highways, water surfaces made by accumulation lakes and agriculturally inefficient surfaces. The total estimation of the power provided from the PV plants is: 3.27GW for the roof tops, 0.034GW for the highways, 1.15GW for the water surfaces and 4.52GW for the agriculturally inefficient surfaces.

This paper describes the implemented system for detecting the state of the containers for collection of municipal waste. The data that is being collected contains following: fullness of the container, the position of the cover, and battery status. The data is transmitted via the Wi-Fi module ESP8266-12E to the broker, where an available management application system utilizes the transmitted data. The communication protocol that was used for that purpose is Message Queue Telemetry Transport (MQTT). The module operates autonomously, with a battery or solar powered source. Defect of efficient waste management has caused serious environmental problems and cost issues. A possible implementation of the system will be presented on the use case of the city of Sarajevo.