Electrical Circuit Research Articles

Circuit synthesis based on a prescribed Lagrangian

On the basis of a prescribed quadratic Lagrangian, an algorithm of synthesis for an electric circuit is suggested here. That is, the circuit evolution equations are equivalent to the relevant Euler–Lagrange equations. The proposed synthesis is a systematic approach that allows one to realize any finite-dimensional physical system described by a quadratic Lagrangian in a lossless electric circuit so that their evolution equations are equivalent. The synthesized circuit is composed of (i) capacitors and inductors of positive or negative values for the respective capacitances and inductances, and (ii) gyrators. The circuit topological design is based on the set of L C LC fundamental loops (f-loops) that are coupled by G L C GLC -links each of which is a serially connected gyrator, capacitor, or inductor. The set of independent variables of the underlying Lagrangian is identified with f-loop charges defined as the time integrals of the corresponding currents. The EL equations for all f-loops account for the Kirchhoff voltage law whereas the Kirchhoff current law is fulfilled naturally as a consequence of the setup of the coupled f-loops and the corresponding charges and currents. In particular, the proposed synthesis provides for efficient implementation of the desired spectral properties in an electric circuit. The synthesis provides also a way to realize arbitrary mutual capacitances and inductances through elementary capacitors and inductors of positive or negative respective capacitances and inductances.

Interdependent Expansion Planning for Resilient Electricity and Natural Gas Networks

This study explores enhancing the resilience of electric and natural gas networks against extreme events like windstorms and wildfires by integrating parts of the electric power transmissions into the natural gas pipeline network, which is less vulnerable. We propose a novel integrated energy system planning strategy that can enhance the systems’ ability to respond to such events. Our strategy unfolds in two stages. Initially, we devise expansion strategies for the interdependent networks through a detailed tri-level planning model, including transmission, generation, and market dynamics within a deregulated electricity market setting, formulated as a mixed-integer linear programming (MILP) problem. Subsequently, we assess the impact of extreme events through worst-case scenarios, applying previously determined network configurations. Finally, the integrated expansion planning strategies are evaluated using real-world test systems.

Towards sustainable urban living: A holistic energy strategy for electric vehicle and heat pump adoption in residential communities

Electric vehicles (EVs) and heat pumps (HPs) are key in reducing carbon emissions from transportation and domestic heating, yet their adoption may increase peak load demands on electrical networks. One of the aims of this research is to assess the potential impact of uncontrolled EV charging on community-scale distribution networks, exploring how this could stress the existing electrical infrastructure. It also explores the role of EVs in Vehicle-to-Grid (V2G) and smart charging applications, aiming to enhance community distribution systems. The study investigates the maximum stabilisation level achievable under various scenarios, highlighting the importance of smart energy management in integrating renewable energy and addressing uncertainties in the modelling process. Additionally, this study discusses the proposed systems' scalability, consumer behaviours' impact on the suggested energy solutions, and the potential implications of recent technological advancements for simulated communities. The research employs a sophisticated, integrative approach, combining stochastic methods with several robust energy software. Key findings suggest that uncontrolled EV charging can lead to grid capacity issues at high EV penetration levels, particularly during colder months. While smart charging and V2G technologies can moderate peak loads in many scenarios, achieving 100 % sustainable technology integration requires enhanced energy management or increased network capacity, especially in winter. Wind and solar power integration demonstrates strategic complementarity, particularly in winter, enhancing the reliability and stability of the community grid. It is also observed that peak solar generation hours misalign with the community's highest demand times, posing challenges for solar energy utilisation in EV charging in residential-based areas.

Optimisation of asymmetries in mm-wave single-element fractal antenna for gain-bandwidth enhancement

ABSTRACT In this study, a low-loss substrate was used to create an Asymmetric Irregular Hexagonal Fractal (AIHF) mm-wave antenna. The antenna consists of an Asymmetric Defected Ground Structure (ADGS) attached to the bottom of a 0.55λ0 ×0.40λ0 ×0.032λ0 mm3 substrate and an Irregular Hexagonal Fractal (IHF) patch on top of the substrate. The proposed fractal technique is unique and based on fractal-slot 3-stage iterations. The IHF patch is created by etching seven fractals arranged symmetrically about the y-axis, one of which has a central 1/3rd (scaling) iteration factor and six hexagonal fractals that are 1/9th of the parent 0th order iteration. On the patch, these fractal slots are evenly spaced out. By etching an Asymmetric Cascaded Double Dumbbell (ACDD) slot on the ground plane, an ADGS is created. With this etching in the patch and ground, a gain of > 5.0 dBi for a −10 dB S11 bandwidth of 4.655 GHz (32.84–37.215 GHz), a recorded peak gain of 13.4 dBi is at 33.55 GHz and an average radiation efficiency of 87.75% is achieved. Using the High-Frequency Structure Simulator (HFSS), the width of ADGS, the position of ACDD on ADGS, and the dimensions of etched fractals are optimised through a pattern search parametric iterative technique. These results are validated using the Vector Network Analyser (VNA), and the Anechoic Chamber and it is revealed that they agree well with the simulated results. The designed AIHF antenna’s RLC electrical equivalent circuit modelling is presented along with evaluated R, L, and C values.

Optimal sizing of multi-energy microgrid with electric vehicle integration: Considering carbon emission and resilience load

To address the intermittency of renewable energy sources, global warming, and increasing load demands, this paper proposes the optimal sizing of a multi-energy microgrid (MEMG) consisting of electrical, thermal, cooling, and hydrogen networks. The system integrates multi-energy storage and EVs along with the resilience load to facilitate a robust operation scheme. The paper introduces an improved resilience backup mechanism for EVs using hybrid storage. Then, random samples for stochastic parameters are generated with Monte Carlo Simulations (MCS). To this end, a mixed-integer linear programming-based model is developed to minimize cost, emissions, and load shed. Then, a CPLEX solver is applied to solve it efficiently. The optimal MEMG with the hydrogen network reduces cost by 4% and emissions by 40%. The case study validates that hybrid storage (BES-HST-TST) can effectively reduce the electricity grid purchase to zero, making MEMG self-sufficient while yielding the least annual system cost (ASC) of 3855562$ and decreasing emissions to 8385 kg, resulting in economic savings, environmental sustainability, and increased utilization of renewables. Notably, V2G can save 0.7546% of MEMG extra cost incurred due to EVs integration and significantly reduces CO2 emissions by 4%. A novel finding is that the proposed hybrid storage backup mechanism can effectively minimize the extra cost of keeping the resilience load by retaining 31.46% of backup in hydrogen form. It mitigates risk associated with power outages while achieving the least ASC of 3858933$ and CO2 emissions of 8043 kg. These results can help realize a green, cost-effective, and efficient energy system.

Application of microbial fuel cell and high voltage booster in the dual cathode electro-Fenton treatment of RO16 dye

The microbial fuel cell (MFC) powered dual cathode electro-Fenton (DCEF) advanced oxidation process was used for the Reactive Orange 16 (RO16) dye treatment. As MFC is known for its high membrane costs and low power densities, we used a single-chamber MFC with anodic cell exposure to air to limit the substrate loss caused by the methanogenesis activity and achieve higher power output. The developed MFC shows 672.20 mW/m3 of maximum volumetric power density (Pmax). Although, the developed MFCs generate renewable energy from wastewater; the resulting power is too low for any practical application. Therefore, we designed here a newly developed low-voltage booster (LVB) to extract useful power. With the low output, the MFC voltage (around 0.4 V) was effectively increased to 12.2 ± 0.02 V without experiencing any voltage reversal problems. Furthermore, even after detaching the LVB from the MFC, the boosted voltage (12.2 ± 0.02 V) was consistently maintained for more than 10 h. We believe that this type of low voltage booted electrical circuit MFC-powered system will offer a more energy-efficient and economical method for treating textile industrial dye pollutants.

Future Distribution Networks: A Review

This manuscript presents a comprehensive review of recent advancements in electrical distribution networks, with a specific focus on the incorporation of direct current (DC) applications. The research aims to comprehensively address the current and future aspects of DC, spanning from the distribution level to the utilization level. The renewed interest in DC power systems has led to the investigation of several transitional challenges in recent years. A significant portion of these efforts has been dedicated to determining the feasibility of applying DC to specific use cases. Additionally, the literature has explored design considerations such as system architecture and voltage levels, the integration of DC into existing distribution networks, load flow (LF) computations, and the distinct safety concerns associated with DC power systems. In this paper, the various research endeavors are categorized, evaluated, and scrutinized to assess the current state of the transition from a purely alternating current (AC) distribution system to a solely DC or hybrid AC/DC distribution system. A bibliometric analysis is conducted, constructing a network of co-occurrence based on author-provided keywords, which reveals the primary research foci in this domain. The barriers hindering the widespread adoption of DC distribution systems and potential solutions are also discussed. Moreover, this article synthesizes ongoing efforts to address these obstacles and delineates future research directions by emphasizing the existing knowledge gaps.

Corona Product of Soft Directed Graphs

Soft set theory, proposed by D. Molodtsov, is a mathematical framework for dealing with uncertain data. Soft set theory is now widely used to solve decision-making problems and has a wide range of applications in economics, engineering, medicine, and other fields, as demonstrated by Molodtsov’s pioneering work. A directed graph is a graph with directed edges. Directed graphs can be used to study and solve problems involving social networks, shortest paths, electrical circuits, and so on. By extending the notion of the soft set to directed graphs, we presented soft directed graphs. Soft directed graphs offer a parameterized perspective on directed graphs. In this paper, we introduce and investigate the corona product and the restricted corona product of soft directed graphs.

A nostalgic trip? Klaus Rifbjerg’s “På Sporet af den Tabte Vogn” and the Copenhagen tramway

For much of the twentieth century, the tramway was the most important public transport system in Copenhagen, Denmark. It played a crucial role in the life of the city and features strongly in Danish art and literature produced during the network's lifespan as well as after it was finally closed in 1972. Despite this, the tramway has only received scarce scholarly attention. This article looks to address the situation. It does so by drawing attention to the fact that although the tramway was shut down, it lived on in art and literature. One example of this is “På Sporet af den Tabte Vogn” (1985) written by Klaus Rifbjerg. This short story has often been described as nostalgic. While this is not a misreading, it is an assessment that requires clarification. A close reading that draws on studies of nostalgia reveals that the short story does not boil down to a sentimental longing for a lost past. Rather, it thematises nostalgia for the Copenhagen tramway, questioning such remembrances’ status and relevance in contemporary society. This means that, ultimately, the short story can be seen as part of a broader tendency in writing about closures of electric public transport networks in Western Europe and North America: it works as a counternarrative to notions of progress, an antidote to predominant ideas of urban development in the mid-twentieth century.

Investigation of an efficient high cooling-capacity Stirling-type pulse tube refrigerator with passive rod displacer operating at 173 K

Pulse tube refrigerator (PTR) with passive rod displacer is of great potential to realize high-efficiency refrigeration and can be a feasible substitute for the vapor compression system in ultra-low temperature cold storage. However, PTRs with passive rod displacer in that application require high efficiency and substantial cooling capacity, which still need to be developed in previous research. In this paper, a high cooling-capacity PTR with passive rod displacer operating at 173 K was designed, fabricated, and investigated. The special property of acoustic power recovery was exhibited based on an electrical circuit analogy model and energy flow analysis. The structural parameters of PTR with passive rod displacer were optimized by one-dimensional numerical software. The experimental results showed that a cooling capacity of 157.5 W at 173 K was obtained with an input electric power of 500 W. The corresponding relative Carnot efficiency reached 21.8 %. The phase difference between the displacer and piston decreased slightly from 58.1° with the increase of cooling temperature when charging pressure and operating frequency were 2.8 MPa and 65 Hz, respectively. The phase difference was determined by the operating frequency and was slightly affected by charging pressure, cooling temperature, and input electric power. Based on the validated numerical models, PTR with passive rod displacer and inertance-tube-type PTR were compared. The numerical results showed that both enthalpy and PV power enlarged at the T-junction in the PTR with passive rod displacer due to acoustic power recovery. According to the acoustic-mechanical–electrical coupling phasor diagram, the phase difference between pressure and piston displacement decreased because of the mass flow superposition at the T-junction, affecting the output capability of the linear compressor. The efficient high cooling-capacity prototype verifies that PTR with passive rod displacer has a bright future in ultra-low temperature engineering applications.

A DC fault current fast-computing method of MMC-HVDC grid with short circuit protection equipment

The multi-terminal modular multi-level converter-based high voltage direct current (MMC-HVDC) grid with short circuit protection equipment (SCPE) is so complex that it is difficult to estimate its fault current and analyze the performance of SCPE by conventional time-domain numerical calculation method, it meets three big obstacles. This paper has made significant progress in overcoming these obstacles. 1). By applying the modern electrical circuit theory, a systematic formulation of the differential equation set for fault current calculation is developed to avoid a lot of complex and cumbersome matrix manual calculations. 2). A novel Y-Delta transformation in the s-domain is proposed to develop an eliminating virtual node approach for a complex MMC-HVDC grid, including the ring, radial, and hybrid topologies. 3). It is difficult to solve the equivalent circuit of MMC-HVDC grid with SCPE since SCPE is a time-variable-nonlinear circuit. A canonical voltage source model of SCPE is established to transform the time-variable-nonlinear circuit into a piecewise linear circuit. Based on the three significant progresses, a DC fault current fast-computing method of MMC-HVDC grid with SCPE is put forward to deal with all kinds of MMC-HVDC grids with several kinds of SCPEs. Then, the performance of several kinds of SCPE is analyzed and compared by this method. Consequently, the proposed DC fault current fast-computing method is a new powerful tool to estimate the fault current of MMC-HVDC grid and analyze the performance of SCPE.

A metaconceptually-enriched argumentation activity for creating the scientific understanding: example of simple electrical circuits

A metaconceptually-enriched argumentation activity for creating the scientific understanding: example of simple electrical circuits

Power Losses Reduction in Three-Phase Unbalanced Distribution Networks Using a Convex Optimization Model in the Complex Domain

This article presents a solution methodology to minimize power losses in three-phase unbalanced distribution networks. This approach involved an efficient complex-domain model that is categorized under mixed-integer convex optimization. The methodology employed consisted of efficient load rotation at each constant power node via a three-phase rotation matrix that allows defining each load connection to minimize the expected power imbalance at the terminals of the substation, as well as the total grid power losses, and improve voltage profile performance at each system phase. The load imbalance, expressed as a percentage, can be defined as a function of the active, reactive, or apparent power. In addition, considering the complex-domain representation of three-phase electrical networks under steady-state conditions, a mixed-integer convex model was formulated to reduce the power imbalances. With the purpose of determining the initial and final power losses of these distribution systems, the successive approximations method was employed to address the three-phase power flow problem. As a result, numerical validations in the IEEE 25-bus system and a 35-node three-phase feeder showed that the final active power losses vary depending on the objective function analyzed. Therefore, for the test feeders studied, it is necessary to evaluate each objective function, with the aim of finding the one that yields the best numerical results. Power losses reductions of about 3.8056 % and 6.8652 % were obtained for both test feeders via the proposed optimization methodology. All numerical validations were performed in the Julia programming environment, using the JuMP optimization tool and the HiGHS solver.

Hybrid cooling system with phase change material and liquid microchannels to prevent thermal runaway propagation within lithium-ion battery packs

Thermal runaway propagation in battery pack can cause catastrophic hazards without timely countermeasures. This paper presents the establishment of lumped thermal resistance model for battery pack and introduces an innovative hybrid thermal management system designed to suppress thermal runaway propagation. First, a heat generation model describing the reaction dynamics of cell thermal runaway is developed and validated by experiment. Subsequently, a lumped thermal resistance network is formulated for the large-scale battery pack using electrical circuit elements and simulation studies for the thermal runaway propagation are carried out. The results reveal that the thermal runaway propagation progress triggered by four cells can accelerate by nearly 40 % compared to that initiated by a single cell. Consequently, a hybrid thermal management incorporating phase change material and liquid microchannels is designed. Comparative analysis with individual cooling systems demonstrates the superior effectiveness of the proposed system in suppressing the first round of thermal runaway propagation. The temperatures of neighbor cells only have a marginal climb to about 80 ℃ in the initial 600 s, which is well below the thermal runaway triggering temperature. This work can provide valuable insights into the structural design of thermal management systems for battery packs in practical applications.

Siting and operating incentives in electrical networks: A study of mispricing in zonal markets

The incentives electricity generators face in investment and output decisions hinge on market design. Under some zonal market designs, where profit-maximizing participants face a uniform regional price, achieving lowest-cost system-wide production can be impossible. Further, zonal designs can incentivize siting of intermittent renewables in inefficient locations behind network constraints, of concern for jurisdictions undergoing a clean energy transition. We develop measures of mispricing that compare the zonal prices generators receive to locational marginal prices that value congestion externalities from generator output. We apply these measures to show wind and solar generators are increasingly siting in constrained areas of the Australian network, and highlight sources of potential efficiency gains from adopting a nodal market design with locational marginal pricing.

OPTIMAL TOPOLOGY OF ELECTRIC CIRCUITS IN PV-PANELS AND PV-PLANTS WITH USING CONTROLLED CONNECTIONS

The article considers the topology of electric circuits of photovoltaic panels and photovoltaic plants. The existing principles of connection are considered, advantages and disadvantages are analyzed. A parallel-serial connection cell for connecting two power sources is proposed. It is possible to implement parallel connection, serial connection and shunt, simultaneously, in one device. Switching in this cell is controlled and dynamic. The topology of combining a large number of photovoltaic devices is demonstrated. A topological structure in the form of a tree is used. The advantages and disadvantages of this approach are shown. A modern technological approach to the implementation of such a controlled system is proposed. Conclusions are made.

Solar-powered single-stage distillation and complex conductivity analysis for sustainable domestic wastewater treatment.

This study investigates the efficacy of a solar-powered single-stage distillation system for treating domestic wastewater, supplemented with complex conductivity analysis. Domestic wastewater samples were collected from a municipal manhole in El Jadida, Morocco, over a 24-h period. The single-stage distillation system, designed for domestic wastewater treatment, utilizes heat to vaporize the wastewater, followed by condensation to produce pure liquid water. The system demonstrated increased distilled water production with rising temperatures, with domestic wastewater outperforming seawater as a feed water source. Physical and chemical testing of the treated water revealed significant improvements in water quality, meeting, or exceeding Moroccan irrigation water standards. Reductions in parameters such as biological oxygen demand (BOD), chemical oxygen demand (COD), suspended matter, and heavy metals underscored the effectiveness of the distillation process. Complex conductivity analysis provided insights into the electrical properties of untreated wastewater and distilled water. Deconvolution of complex conductivity data using an equivalent electrical circuit model elucidated the electrochemical processes during treatment, highlighting the efficiency of the distillation process. The integration of solar energy addresses water scarcity while promoting environmental sustainability. Complex conductivity analysis enhances process understanding, offering avenues for monitoring and control in wastewater treatment.

Observation of thunderstorm-induced muon events in GRAPES-3 experiment

The GRAPES-3 tracking muon telescope located at Ooty (India) records short-term variations in the muon intensity during major thunderstorms, termed thunderstorm-induced muon events (TIMEs). Its excellent angular resolution, coupled with high statistics, allows us to observe subtle directional variations in muon rate. We detected 169 statistically significant events during the five-year period from 2006 through 2010. The monthly and seasonal variation patterns of the observed TIMEs were discussed, emphasizing their occurrence and climatological aspects. The annual diurnal pattern was plotted with the Carnegie curve, considering their possible causal link with the global electric circuit. The work represents the first report from any experiment for such an extended period in an uninterrupted manner.

Digitalization for Operational Management of Electric Networks

The article discusses digitalization issues for managing electrical networks and the basic principles of digitalization. Examples of digitalization are given, such as the allocation of events and their intelligent processing, analysis of emergencies, and the search for damage in branched electrical networks. The verification algorithm for current meters based on redundant measurements is considered.

Dynamic characteristics testing and modeling in electromagnetic-thermal-force coupling of electromagnetic devices using parallel finite element simulation

Electromagnetic systems of Electromagnetic devices involve multiphysics coupling of electromagnetic fields, electrical circuits, mechanical motion, and temperature fields. When the digital prototype model has a large number of meshes, the commercial finite element software also has the disadvantage of long computation time in the simulation of dynamic characteristics of electrical apparatus. This paper proposes a transmission line method (TLM) based digital modeling method for the electromagnetic-thermal-force coupling to test and evaluate the static and dynamic characteristics of electromagnetic devices more accurately and efficiently. The case study is developed on a direct current (DC) contactor, and the dynamic characteristics testing and modeling in the electromagnetic-thermal-force coupling of the contactor are investigated. The numerical results of the finite element method (FEM) model for the electromagnetic system of the contactor are compared with the commercial FEM software Altair Flux and the experimental results, which demonstrate the exceptional accuracy of the proposed digital modeling method for the multiphysics coupling of the DC contactor. Meanwhile, the dynamic characteristics of the DC contactor at different ambient temperatures are measured and evaluated, and the comparison with the experimental measurements shows the applicability of the proposed digital prototype model at different ambient temperatures. Compared with the conventional Newton-Raphson (NR) iteration, when dividing fine mesh and extremely fine mesh, the TLM parallel computing significantly improves the efficiency of solving the dynamic characteristics of multiphysics coupling by about 35 % and 44 % with the same computational accuracy, respectively. The dynamic characteristics evaluation method combined with digital modeling technology and experimental measurements proposed in this paper demonstrates high accuracy and solving efficiency, making a notable contribution to the field of design and optimization of electromagnetic devices.