Showing papers on "Electrical network published in 2022"

Implementation of an accurate method for the analysis and simulation of electrical R‐L circuits

Abstract: In this study, we propose to introduce and apply an accurate numerical procedure to solve the mathematical model of fractional order, which describes the electrical circuits composed of resistors and inductors (RL) driven by a voltage of the current source. Our research is based on the spectral collocation method, which utilizes the advantageous characteristics of the third‐order Chebyshev polynomials. Some convergence analysis and error theorems are presented. The proposed research concludes by comparing the approximate solutions obtained for the considered model to the exact solution obtained in the classical case. The derived conclusions are further subjected to illustrative graphical and numerical examinations.

Coupling electromagnetic numerical models of HTS coils to electrical circuits: multi-scale and homogeneous methodologies using the T-A formulation

Abstract: Numerical simulation is an effective tool for predicting the electromagnetic behavior of superconductors. Recently, a finite element method-based model coupling the T-A formulation with an electrical circuit has been proposed: the model presents the superconducting constituent as a global voltage parameter in the electrical circuit. This allows assessing the overall behavior of complex high-temperature superconductor (HTS) systems involving multiple power items, while keeping a high degree of precision on the presentation of local effects. In this work, the applicability of this model has been extended to large-scale HTS applications with hundreds or thousands of tapes by referring to two widely recognized methodologies, multi-scale and homogenization, to improve the computation efficiency. Based on the two approaches, three different models were developed and their effectiveness was assessed using the case study of a 1000 turn cylindrical HTS coil charged by a DC voltage source. The comparison of the calculated global circuit parameters, local field distributions, losses, and computation time proves that the computation efficiency can be improved with respect to a model simulating all HTS tapes, without compromising accuracy. The results indicate that the developed models can therefore be efficient tools to design and optimize large-scale HTS devices used in electrical machines and power grids. It is also found that the inductance of an HTS coil is varied according to the transport current and can be even higher than that of a normal conductor coil with the same geometry. We attribute this result to the superconductor’s non-uniform current distribution and relaxation effect during the dynamic process.

Chemical Wave Computing from Labware to Electrical Systems

Abstract: Unconventional and, specifically, wave computing has been repeatedly studied in laboratory based experiments by utilizing chemical systems like a thin film of Belousov–Zhabotinsky (BZ) reactions. Nonetheless, the principles demonstrated by this chemical computer were mimicked by mathematical models to enhance the understanding of these systems and enable a more detailed investigation of their capacity. As expected, the computerized counterparts of the laboratory based experiments are faster and less expensive. A further step of acceleration in wave-based computing is the development of electrical circuits that imitate the dynamics of chemical computers. A key component of the electrical circuits is the memristor which facilitates the non-linear behavior of the chemical systems. As part of this concept, the road-map of the inspiration from wave-based computing on chemical media towards the implementation of equivalent systems on oscillating memristive circuits was studied here. For illustration reasons, the most straightforward example was demonstrated, namely the approximation of Boolean gates.

Solving Electrical Circuits via Graph Theory

Abstract: Solving for currents of an electrical circuit with resistances and batteries has always been the ultimate test of proper understanding of Kirchoff’s rules. Yet, it is hardly ever emphasized that a systematic solution of more complex cases requires good understanding of the relevant part of Graph theory. Even though this is usually not covered by Physics’ curriculum, it may still be of interest to some teachers and their mathematically inclined students, who may want to learn details of the rigorous approach. The purpose of this article is to provide a concise derivation of a linear set of equations leading to a unique solution of the problem at hand. We also present a simple computer program which builds such a solution for circuits of any textbook size.

Comparison of short-circuit current in AC and DC shipboard electrical power distribution systems: A case study of 17,500 DWT tanker vessel

Abstract: The current ability of power electronic devices increases the possibility to change the shipboard electrical power distribution system from widely-used alternating current (AC) to direct current (DC) systems. DC distribution systems has been known to offer higher power efficiency compared with AC distribution systems. However, the decision to move the shipboard electrical power distribution systems to DC systems requires more information in technical aspects aside of power efficiency. In this study, the investigation to compare short-circuit current between AC and DC distribution systems in non-electric propulsion vessel is conducted. The investigation is performed for electrical power distribution system of 17,500 DWT tanker vessel. Short-circuit current profile for both systems are obtained from simulation in computer software. The results indicate that the DC shipboard electrical power distribution systems has lower short-circuit current than the AC system for the same vessel.

Equivalent circuit modeling and analysis of aerodynamic vortex-induced piezoelectric energy harvesting

Abstract: Abstract Low-speed wind energy has potential to be captured for powering micro-electro-mechanical systems or sensors in remote inaccessible place by piezoelectric energy harvesting from vortex-induced vibration. Conventional theory or finite-element analysis mostly considers a simple pure resistance as interface circuit because of the complex fluid-solid-electricity coupling in aeroelastic piezoelectric energy harvesting. However, the output alternating voltage should be rectified to direct voltage to be used in practical occasions, where the theoretical analysis and finite-element analysis for complex interface may be cumbersome or difficult. To solve this problem, this paper presents an equivalent circuit modeling (ECM) method to analyze the performance of vortex-induced energy harvesters. Firstly, the equivalent analogies from the mechanical and fluid domain to the electrical domain are built. The linear mechanical and fluid elements are represented by standard electrical elements. The nonlinear elements are represented by electrical non-standard user-defined components. Secondly, the total fluid-solid-electricity coupled mathematical equations of the harvesting system are transformed into electrical formulations based on the equivalent analogies. Finally, the entire ECM is established in a circuit simulation software to perform system-level transient analyses. The simulation results from ECM have good agreement with the experimental measurements. Further parametric studies are carried out to assess the influences of wind speed and resistance on the output power of the alternating circuit interface and the capacitor filter circuit. At wind speed of 1.2 m s −1 , the energy harvester could generate an output power of 81.71 μ W with the capacitor filter circuit and 114.64 μ W with the alternating circuit interface. The filter capacitance is further studied to ascertain its effects on the stability of output and the settling time.

An Energy-Based, Always Index $\leq$ 1 and Structurally Amenable Electrical Circuit Model

Abstract: Combining three themes---port-Hamiltonian energy-based modeling, circuit structural analysis, and structural analysis of differential-algebraic equations---we form a new model for electrical circuits, the compact port-Hamiltonian equations. They have remarkable simplicity and symmetry and always have index at most 1 and other good numerical properties. The method has been implemented in MATLAB. We give proofs and numerical results.

Mathematical Modeling of Electrical Circuits and Practical Works of Increasing Difficulty with Classical Spreadsheet Software

Abstract: This paper presents a modeling practical works project of electrical engineering, proposed to the first-year students of the University Institute of Technology in France, during the COVID-19 pandemic. The objective of this paper is twofold. The first objective is to present to the students the opportunities of modeling and calculation development of a spreadsheet software in their professional lives. The second objective is to create a file that automatically calculates all the current and voltage values at each point of any alternative electrical circuit. The aim of this paper, geared toward students, is to bring them to build their own numerical remote lab, autonomously. Therefore, pedagogical keys are given along the reading of this document to help them to progress, both on electrical circuits conceptual understanding with series and parallel RLC circuits and on their computation in a spreadsheet software. As a conclusion, this paper can be used as a base to develop remote modeling practical works of many and different devices, as well as a database starting point of such analytical models.

Optimal Experimental Design for Parametric Identification of the Electrical Behaviour of Bioelectrodes and Biological Tissues

Abstract: The electrical behaviour of a system, such as an electrode–tissue interface (ETI) or a biological tissue, can be used for its characterization. One way of accomplishing this goal consists of measuring the electrical impedance, that is, the opposition that a system exhibits to an alternating current flow as a function of frequency. Subsequently, experimental impedance data are fitted to an electrical equivalent circuit (EEC model) whose parameters can be correlated with the electrode processes occurring in the ETI or with the physiological state of a tissue. The EEC used in this paper is a reasonable approach for simple bio-electrodes or cell membranes, assuming ideal capacitances. We use the theory of optimal experimental design to identify the frequencies in which the impedance is measured, as well as the number of measurement repetitions, in such a way that the EEC parameters can be optimally estimated. Specifically, we calculate approximate and exact D-optimal designs by optimizing the determinant of the information matrix by adapting two of the most algorithms that are routinely used nowadays (REX random exchange algorithm and KL exchange algorithm). The D-efficiency of the optimal designs provided by the algorithms was compared with the design commonly used by experimenters and it is shown that the precision of the parameter estimates can be increased.

Static, Dynamic, and Signal-to-Noise Analysis of a Solid-State Magnetoelectric (Me) Sensor with a Spice-Based Circuit Simulator

Abstract: Modeling the non-electrical processes by equivalent electrical circuits is a widely known and successfully used technique in research and development. Although finite element methods software development has supplanted electrical analogy techniques due to greater accuracy and intuitiveness in recent decades, the modeling of physical processes based on analogies has several advantages in some cases. Representation of physical processes in the form of lumped circuits and graphs allows researchers to estimate the system with an alternative view, use standardized methods for solving electrical circuits for non-electrical systems, and, most importantly, allows us to use electrical circuit simulators with their unique capabilities. Of particular interest for using the analogy technique are systems that include electronic components along with components belonging to other physical domains, such as mechanical, thermal, magnetic, and others. A solid-state magnetoelectric (ME) sensor equipped with a charge amplifier is proposed in this study as an example of analysis using the equivalent electrical circuit and simulating these circuits using SPICE-based circuit simulators. Sensor analysis is conducted with an emphasis on noise budgeting and optimizing the sensor’s signal-to-noise ratio and resolution. In addition, the steady state, the phasor, and transient types of analyses were employed to study the static and dynamic behavior of the system. Validation of the model using analytical calculations and comparison with experimental data demonstrated superior results.

Electrical Response Analysis of a Piezoelectric Energy Harvester Power Source Based on Electromechanical Parameters

Abstract: A piezoelectric energy harvester generator is a device capable of transforming environmental mechanical energy into electrical energy. The piezoelectric electromechanical parameters determine the maximum electrical power which is able to be transferred to an electric load. In this research work, an exhaustive study of the electromechanical parameters related to the piezoelectric material is carried out, modeling them as components of an electrical circuit, in order to analyze their influence on the transmitted power. On the other hand, some electrical loads are simulated to determine different matrix scenarios for a model developed by state-space equations in the Laplace transform domain. The results obtained have allowed to know how the piezoelectric material properties and mechanical characteristics influence the electrical power output of the energy harvester generator and the energy transmission behavior for different electric loads. The conclusions show how the different electromechanical parameters are related to each other, and how their combination transforms the mechanical environmental energy into the required electrical energy. The novelty of this research is the presentation of a model capable of obtaining the optimized working point of the harvester, taking into account not only the electric loads and current demands but also the piezoelectric material parameters.

Mathematical Models for Determining Areas of Static Stability in Electrical Networks with Distributed Generation Plants

Abstract: There is now an increased interest in distributed generation (DG) plants located in close proximity to power consumers; at the same time, it is assumed that a significant number of the DG facilities utilizes renewable energy resources. The wide use of DG technologies in electrical energy systems (EES) requires development of new control algorithms in normal, emergency, and postemergency modes. The issues of determining limit loads for the EES equipped with DG plants are of particular importance. These plants can be removed from the consumption centers, which leads to a ‘narrowing’ of static aperiodic stability (SAS) areas. This paper presents the results of studies aimed at developing methods for determining the SAS areas in the EES equipped with DG plants. On the basis of the limiting mode equations, an effective technique for determining the EES stability areas with DG plants for various network structures were propose, and the results of building SAS areas for an electrical network with distributed generation were present. Additionally, simulation of transient processes in the EES under study were carried out for various points in the space of the mode controlled parameters in MATLAB.

Electrical distribution grid of Kirkuk City: A case study of load flow and short circuit valuation using ETAP

Abstract: The load flow study and short circuit analysis can be considered as the backbone of the electrical power network. This study based on real data collected from 12 substations, each substation contains many feeders provide the electricity network of Kirkuk city (a city in Iraq located at the north of Baghdad). The methodology of this article depended on using the Electrical Transient Analyzer Program (ETAP) software in assessing the performance of Iraqi electrical distribution network (Kirkuk city as a model) by starting modeling and simulation in order to assess the reliability through testing the load flow, and short circuit test. A complete study of load flow assessment of an actual Kirkuk city power distribution network with actual load values is presented (data have been taken from the Directorate of Electricity Distribution of Kirkuk city). The results of modeling the whole city and the detailed reports of this study can give us a comprehensive assessment with the presence of actual loads values, including total demand, PF, transmission line parameters, and the weakness points of the electrical grid.

Improving the Accuracy of Determining the Location of Short Circuits in Electrical Networks with a Nominal Voltage of 110-150 kV

Abstract: The article is devoted to the study of improving the efficiency of the electric network with a voltage of 110-150 kV through the use of a developed device FKZ, which uses a radio channel to transmit information. At the present stage of development of electric power industry the question of reliability of work of high-voltage electric networks plays an important role. During the operation of such electrical networks, emergencies inevitably occur, the most dangerous of which are short circuits. Determining the location of damage to the electrical network is the most complex, time-consuming and time-consuming technological operation with significant costs. Therefore, the task of improving the design of devices to determine the location of damage, the use of which will significantly reduce the level of operating costs for electrical networks, is relevant. One of the ways to solve the problem of improving the accuracy of determining the location of a short circuit in the electrical network is the use of special technical means - short circuit clamps. The scheme of the normal regime of the 150 kV electric network of PJSC Kirovogradoblenergo was used for the research. The analysis of the configuration of this network showed that it has a number of substations that receive power from transmission lines, which are deaf branches. Therefore, the installation of short-circuit latches on such lines is necessary. The authors of the article propose the introduction of a radio channel to transmit information about the state of the network and the place of damage to the next personnel of the substation. The most appropriate ways to organize a radio channel are: the use of GSM networks; use of unlicensed frequency transmitters. Approximate calculations have been carried out, which confirm the possibility of creating a radio channel for transmitting information from the short-circuit lock for a distance of up to 20 km, using transceivers of non-licensed frequencies.

Applications of Electrical Simulators for Analyzing Hydraulic Pipe Networks

Abstract: Water distribution networks (WDN) need to be analyzed multiple times for optimal design. Analyzing WDN requires solving non-linear simultaneous equations. For this purpose, many algorithms and models are developed. By using these algorithms several simulators (both freely available and commercial) are developed for analyzing WDN. In this paper, by using the analogy between electrical and hydraulic networks, hydraulic elements such as pipes, meters, valves, and pumps are modeled in Verilog-A. The reservoirs are replaced with voltage sources and demands with current sources. An electrical freeware called QucsStudio is chosen for implementing the hydraulic networks. The applicability of the electrical simulator through Verilog-A coding to analyze realistic WDNs is demonstrated. EPANET simulation results are taken as reference values for accuracy verification of the proposed scheme. The electrical simulator is shown to be providing sufficiently accurate results in terms of heads at junctions and discharges through pipes. It is found that the electrical simulator takes less simulation time than the EPANET. Also, other electrical analysis techniques and equivalent electrical parameter extraction schemes (such as finding Thevenin or Norton equivalents, source and impedance transformation, etc.) can be easily executed using an electrical circuit simulator. Therefore, hydraulic engineers can use a circuit simulator using the proposed methodologies for quick analysis of WDNs.

The 0.38 kV electrical networks unbalancing operating modes optimization

Abstract: The equipment 0.38 kV low-voltage electrical networks is not a satisfactory level. Such electric networks operating modes management is carrying out save energy measures and electricity supply improve efficiency in general largely allows. As a result, the electric energy supplied parameters obtaining actual nature information about to consumers through these electric networks is the developing the power transmission requirements measures basis comply. The article presents results current unbalancing modes objective studies in 0.38 kV an electrical network that feeds Irkutsk multi-storey residential building electric consumers. The analysis electric energy parameters, power quality indicators changes as well as electricity lo sses caused by the currents unbalance in the studied electric network are presented. The calculate parameters and using results of balancing device efficiency as well as its influence on the quality indicators studied and electrical energy loss in the studied electrical network are presented.

Rho: Application to Analyze Electrical Resistivity

Abstract: Electrical resistivity measurements of metals often use the four-wire method, where data acquisition alternates between temperature and voltage. The temperature and voltage values are similar and manual selection of each set of measurements is time consuming. Rho is intended to make electrical resistivity data analysis faster and more reliable by automatically selecting the temperature and voltage measurements using signal processing. The time required to process 52 data points (which consists of approximately 6000 measurements) using Rho is less than one minute compared to up to 4 hours for manual processing. Rho is stored in FigShare and can be used by any research group conducting alternate temperature and voltage measurements to obtain electrical resistivity at either ambient or extreme conditions.

Categories of Kirchhoff relations

Abstract: It is known that the category of affine Lagrangian relations, AffLagRel_F, over a field, F, of integers modulo a prime p (with p > 2) is isomorphic to the category of stabilizer quantum circuits for p-dits. Furthermore, it is known that electrical circuits (generalized for the field F) occur as a natural subcategory of AffLagRel_F. The purpose of this paper is to provide a characterization of the relations in this subcategory -- and in important subcategories thereof -- in terms of parity-check and generator matrices as used in error detection. In particular, we introduce the subcategory consisting of Kirchhoff relations to be (affinely) those Lagrangian relations that conserve total momentum or equivalently satisfy Kirchhoff's current law. Maps in this subcategory can be generated by electrical components (generalized for the field F): namely resistors, current dividers, and current and voltage sources. The "source" electrical components deliver the affine nature of the maps while current dividers add an interesting quasi-stochastic aspect. We characterize these Kirchhoff relations in terms of parity-check matrices and in addition, characterizes two important subcategories: the deterministic Kirchhoff relations and the lossless relations. The category of deterministic Kirchhoff relations as electrical circuits are generated by resistors circuits. Lossless relations, which are deterministic Kirchhoff, provide exactly the basic hyper-categorical structure of these settings.

Using Artificial Neural Network to Speed Up the Study of the State of Electrical Systems

Abstract: The objective of this article is to use Artificial Intelligence (AI) method to study the state of electrical networks. The state of a network is described by its state variables, such as the voltage at the buses of a network or the currents flowing in the sections of a network. Power flow analysis is a basic tool for planning an electrical power system. Power flow is a non-linear problem. Therefore, the solution to this type of problem can be found using iterative numerical methods or Artificial Intelligence methods. In this paper, the method of Artificial Neural Network (ANN) has been used to predict voltage magnitudes and voltage phase angles of the I3E 14 bus system and a real network of Morocco ONEE 24 bus system. After testing several Neural Network models, it has been possible to propose an architecture with one hidden layer and Levenberg-Marquardt backpropagation as a training function. The results obtained by using this method have been positive and precise compared with the results obtained by the reference method Newton-Raphson. This means that this method can be used to get results in real time, in case of lack of data from the studied system and also where the deterministic methods do not converge.

Development and Research of Method in the Calculation of Transients in Electrical Circuits Based on Polynomials

Abstract: Long electromagnetic transients occur in electrical systems because of switching and impulse actions As a result, the simulation time of such processes can be long, which is undesirable. Simulation time is significantly increased if the circuit in the study is complex, and also if this circuit is described by a rigid system of state equations. Modern requests of design engineers require an increase in the speed of calculations for realizing a real-time simulation. This work is devoted to the development of a unified spectral method for calculating electromagnetic transients in electrical circuits based on the representation of solution functions by series in algebraic and orthogonal polynomials. The purpose of the work is to offer electrical engineers a method that can significantly reduce the time for modeling transients in electrical circuits. Research methods. Approximation of functions by orthogonal polynomials, numerical methods for integrating differential equations, matrix methods, programming and theory of electrical circuits. Obtained results. Methods for calculating transients in electrical circuits based on the approximation of solution functions by series in algebraic polynomials as well as in the Chebyshev, Hermite and Legendre polynomials, have been developed and investigated. The proposed method made it possible to convert integro-differential equations of state into linear algebraic equations for images of time-dependent functions. The developed circuit model simplifies the calculation method. The images of true current functions are interpreted as direct currents in the proposed equivalent circuit. A computer program for simulating the transient process in an electrical circuit was developed on the basis of the described methods. The performed comparison of methods made it possible to choose the best method and a way to use it. The advantages of the presented method over other known methods are to reduce the simulation time of electromagnetic transients (for the considered examples by more than 6 times) while ensuring the required accuracy. The calculation of the process in the circuit over a long time interval showed a decrease and stabilization of errors, which indicates the prospects for using research methods for calculating complex electrical circuits.