Abstract

This paper uses a bibliometric research approach to systematically analyse the tendences of research literature on Hybrid Power Supply Systems (HPSS) for standalone houses. The study explores the integration of hybrid energy solutions in residential applications, focusing on key areas such as design, supply strategies, and system control. A review of existing research reveals that while standalone energy systems are well-documented, studies addressing the combined aspects of hybrid system design, supply, and advanced control mechanisms remain limited. This gap highlights the need for more holistic approaches that consider the interaction between energy sources, management systems, and sustainability goals. Emphasis is placed on monitoring and control technologies, which are critical for optimizing system performance but are often explored in isolation from supply strategies. The analysis further shows that the complexity of research topics tends to narrow as more specific concepts are combined, resulting in significantly fewer studies that integrate all key aspects. Comprehensive studies addressing the full spectrum of hybrid design, supply, and control mechanisms are rare, with only one paper found in both Scopus and IEEE databases that covers these areas simultaneously. This indicates an important research gap and underscores the potential for future interdisciplinary work in developing sustainable HPSS for standalone houses in remote and off-grid settings.

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Abstract

Cogeneration is defined as the process of simultaneous production of heat and electricity, with the same installation (heat engine-electric generator group, turbine, etc.). Unlike classic Thermal Power Plants, cogeneration plants can be sized in correlation with the thermal energy requirement, which means that electricity is considered a “secondary” product. Throughout the article, taking into account the general theoretical aspects of the definition and operation of cogeneration systems, through the prism of specific energy indicators, the results obtained in the case of the implementation of a cogeneration system that uses the energy potential of gases are studied of combustion, for the production of the thermal agent for heating and preparation of hot water for consumption. of steam. From a functional point of view, at the level of a refinery, three superheated steam networks are needed, corresponding to three different pressure domains, which means that the results obtained in the study as the case may be, to refer to three distinct modes of operation of the cogeneration system. The main purpose of the operation of such a system for the combined production of electrical and thermal energy is to obtain as much energy as possible in the form of mechanical work by expanding steam in the turbines.

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Abstract

The aim of this paper is the implementation and validation of a mobile phone remote connection to a Supervisory Control and Data Acquisition system (SCADA) of a railway traction substation. The implementation was done not only to optimize the time in which the user intervenes within the electrical substations, in case of a fault or other event, but mostly to be able to react in unforeseen situations where the person in charge is not and cannot quickly reach the electrical substation or even the remote desktop. For this, the operator can connect to the system using the mobile phone and the corresponding mobile phone software using an interface similar to the remote desktop. Therefore, the operator can hand the fault and make the required actions or improvements. The proposed system gives the ability to optimize the intervention costs considering the required trips to the electrical substation, and even more the trip to the SCADA remote desktop station. Therefore, a wireless remote connection method is approached via the mobile phone network to the SCADA system.

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Abstract

This paper emphasizes, once again, the importance of ventilation systems for ensuring thermal comfort in industrial spaces. For this purpose, a dynamic fault regime of variable reluctance synchronous motors (RSM) used to drive such systems (case of occurring an accidental resistive torque) is analyzed from a theoretical point of view (with experimental confirmation). At the beginning, an introduction in the issues of the paper is made. A brief bibliographic analysis and some relevant images regarding the air flow driven by industrial ventilation and air conditioning systems are presented. In order to analyze dynamic regimes of RSM, a Matlab program was carried out, by using a mathematical model written in the two axes theory. A series of graphs have been obtained by running it for a specific case; they emphasize the evolution over time of the main electrical, magnetic and mechanical quantities of the motor. There have been obtained different evolutions of the operation points in various coordinates (phase current, longitudinal and transverse currents of the stator and rotor, magnetization current, magnetization flux, magnetization flux components, torque and speed). The graphs obtained led to a series of relevant conclusions regarding the behavior of the driving motor of the installation (conclusions regard the way in which an increase in the resistant torque influences the values and durations of the analyzed dynamic quantities). The paper ends with Acknowledgment and the corresponding References.

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Abstract

This paper presents a series of simulations for the operation of a reluctance synchronous motor with continuous rotation (RSM), used for air heaters heating industrial buildings. The introduction aims at presenting the domain we analyze. On this occasion, several possibilities for mounting air heaters for industrial buildings are specified. Their operating methods are specified, with emphasis on the case of the reluctance synchronous motors. The mathematical model of these motors, written in the two axes theory, is detailed below; the significance of the quantities used is specified. With the help of this model, a Matlab program was carried out, for simulating the dynamic regimes, specific to the driving motor of air heaters. The paper presents a series of simulations, obtained by means of this program. The simulations regard a fault situation, materialized in an accidental decrease of the motor supply voltage. The graphs obtained refer to the main electrical, mechanical and magnetic quantities specific to the motor. They are accompanied by several relevant conclusions that emphasize the behavior of the motor in the analyzed dynamic regime. The following aspects are regarded: the evolution of the operation point, the influence on the phase current, the influence on the magnetization flux and the rotor speed. These characteristics were experimentally confirmed (indirectly) by emphasizing, in steady state, the evolution of the phase current for the initial and fault cases. The paper ends with references, organized in the order of citations.

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Abstract

The paper presents an automatic system for compacting metal, plastic and glass waste from food consumption (boxes or empty cans). The compaction process is found in waste recycling systems. The purpose of this work is to analyze the main stages of designing an electro-pneumatic drive and automation system for a waste compactor used in food packaging, starting with the creation of the specifications document and ending with the development of a control structure in a classic version – control circuits with contacts and relays, or by using programmable logic controllers (PLCs). To design and validate the control circuits, the FLUIDSIM simulation environment was used, and the experimental validation involved building a functional small-scale model of the compaction device and analyzing its operation in laboratory conditions. Additionally, aside from the educational and research goals, which involve proposing a solution and verifying it through numerical simulation and on a small-scale experimental model, the work also aims to integrate the proposed solution into an automated packaging collection equipment within the Deposit-Return System (SGR). Packaging collection machines located in commercial centers do not have compaction modules integrated into their structure, and thus blockages often occur due to the rapid filling of the collection containers. The introduction of compaction modules would significantly reduce the waste volume and transportation costs for the collection centers.

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Abstract

This paper presents the importance of finding the suitable configurations for Artificial Intelligence and Machine Learning algorithms and correct data preprocessing for a waveform problem. In the Artificial Intelligence and Machine Learning area, this step is one of the most important and it influences the performance result of the model. The experiments of different configurations were done using National Instruments Automated Machine Learning (NI AutoML), a web application created for everyone that allows us to easily change the configurations of the model by just clicking some buttons. This work shows how the model performance is influenced by modifying what columns of data to use, by data splitting or by adding or deleting preprocessing steps in the pipeline. All the results obtained for the different experiments are analyzed in this paper. The proposed flow is generic enough to be applied for all the use cases. To exemplify the whole process, a synthetic data set obtained by generating current and voltage in an RL circuit was chosen and the experiments part was created. The data represent two waveforms: one for current and one for voltage and they represent data recorded during the test time. In the end process each test has a label associated: Pass or Fail. The classification problem was defined for help in improving the fail detection rate.

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Abstract

The paper presents two optimization methods based on the concept of design of experiments: the method by zooms and the method by slidings of designs. Two application variants are presented for each of them. One of the variants only requires access to the values of the objective function at different points in the feasible domain, grouped in designs of experiments, arranged successively, towards the most convenient values. The other variant uses the same technique, but the advance of the designs towards the optimal value is based on the information provided by second-order polynomial models that approximate the objective function on each design, which facilitates the convergence speed of the algorithm. The methods under discussion lend themselves very well to numerical simulations using the finite element method that can provide the values of the objective function at any point in the feasible domain that corresponds to a unique configuration of the simulated device. The paper presents a comparative study of the application of these methods in the two variants, on a 2-D numerical model of an electromagnetic device. Both in the case of the method by zooms and in the case of the method by slidings of designs, the results highlight the simplicity of the first application variant but also the high speed of convergence of the second one, especially for the method by zooms.

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Abstract

The paper presents how the physical phenomenon, corona discharge, can be assessed using     circuits for measuring partial discharges (PD) and radio disturbances. In test circuits for PD measurement, corona discharges may also be present as a disturbing element at certain test voltages, even if all measures are taken to avoid them.

The main features and differences between the PD measurement circuit and radio interference voltage measurement circuit are presented, which include the measurement systems and their calibration methods. So for the PD measurement are presented calibration of the PD circuit with the same impulse charge but using different type of filters at PD instrument (wideband and narrowband). For the radio interference voltage measurement is presented calibration of the test circuit with the same voltage but with using different frequencies at the electromagnetic interference receiver.

In a test circuit simulating the occurrence of corona discharges, corona discharges were evaluated at different test voltages using the same measurement frequencies for the two systems. Differences were observed between the results obtained with the same measurement frequencies for the two systems, differences that were maintained regardless of the measurement system used.

The UV spectrum and the electric field of these discharges are correlated with the applied voltage. To assess the corona discharges, the electric field generated by these discharges at the highest test voltages was also measured.

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Abstract

The design of power transformers is heavily influenced by their performance during short circuit. This paper explores the experimental analysis of a power transformer with circular concentric coils, utilizing metal foil conductor in the low-voltage winding, and a rated power of 2000 kVA. To validate its behavior, the study employs Frequency Response Analysis (FRA), a widely recommended diagnostic method for identifying internal faults in power transformers. Furthermore, the paper provides insights into the design specifics of power transformers used in renewable energy power plants. By highlighting the unique aspects and criticalities examined, this study establishes itself as a niche contribution to understanding safety in transformer operation. The research also delves into experiments conducted in a high-power laboratory to investigate how transformers respond to the dynamic effects of short circuit. Particular attention is given to the thermal and mechanical impacts of short circuit currents, with an emphasis on their negative consequences. Additionally, the paper discusses a system configuration where direct current (DC) produced by photovoltaic cells is converted into alternating current (AC) using one or more inverters connected to the low-voltage windings of a step-up transformer. Finally, the study underscores the importance of assessing the short circuit behavior of power transformer, focusing on the irreversible deformations caused by axial and radial forces during short circuit events.

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