Ferroresonance is a complex and potentially destructive phenomenon that poses significant risks to the reliability and stability of power distribution systems. Although incidents have been documented for more than a century, the underlying mechanisms and effective countermeasures remain only partially understood. This paper presents a structured technical review of ferroresonance in power distribution networks, integrating historical developments, classical analytical modelling, documented damage mechanisms, and mitigation strategies within a unified analytical framework. A classical analytical approach is employed to examine system behaviour, providing a consistent foundation for interpreting previously reported case studies and simulation results. Rather than proposing a new nonlinear model, the study consolidates and critically synthesizes existing theoretical and practical knowledge to offer a comparative perspective on the fundamental physical mechanisms of ferroresonance and the associated engineering mitigation strategies. Particular emphasis is placed on the systematic evaluation of mitigation approaches, including transformer core design modifications, capacitance management practices, deliberate damping techniques, and surge arrester applications, assessed in terms of effectiveness, practicality, and operational impact. The key finding is that there is an engineering trade-off between costly design-stage modifications that improve inherent ferroresonance immunity and retrofit suppression measures, such as lightning arresters, that effectively mitigate ferroresonance in existing installations without reducing normal operating efficiency.
The ubiquitous utilization of three-phase squirrel cage induction motors in numerous commercial and industrial sectors gives them a special place in the academic arena. The excellent properties of these motors, including ease of construction, robustness, and low manufacturing costs, make them superior to other motor types. The fact that these motors operate at approximately a fixed speed initially limited their usage in applications where speed regulation is required. However, with the development of power electronics and the introduction of motor drives, these motors have regained their position. While readers can easily find several resources on the basic operating principles of these motors, this article aims to present a single article that gathers the essence of these references, along with the systematic execution of one of the most popular drive types—indirect field-oriented control—in MATLAB/Simulink. This article is mainly intended for university students and new researchers in this field.
This paper presents an intelligent analytical framework for enhancing voltage stability in radial distribution networks through optimal distributed generation (DG) placement and composite load modeling. A novel voltage stability index (VSI) is formulated to identify weak buses, while a fuzzy inference system integrates VSI, power-loss reduction, and feeder distance to determine the most suitable DG location. The optimal DG capacity is derived using a quadratic curve-fitting method that minimizes real-power losses. The proposed approach is validated on the IEEE 10-bus test system using MATLAB/PSAT simulations. Results reveal that placing a Type-I DG of approximately 2.6 MW at Bus 10 increases the minimum bus voltage from 0.895 p.u. to 0.971 p.u., reduces total real-power losses by 64.2%, and improves the voltage stability margin by 41.7% compared to the base case. The fuzzy–analytical hybrid approach demonstrates robust performance under composite load conditions and provides an interpretable, computationally efficient strategy for planning DG integration in modern distribution networks.
This article presents a streamlined overview of Fourier, Laplace, and Z -transforms for a sophomore- or junior-level signals and systems course in electrical/computer engineering and engineering technology programs. Transform methods are introduced after foundational circuit analysis and serve as prerequisites to studies in communications, controls, power, and signal processing. Conventional textbooks define transforms formally and rely on tables of properties and transform pairs, often assuming prior mathematical preparation. However, this approach is challenging for engineering technology students, who may have completed only Calculus I and II yet are expected to meet ABET-driven learning outcomes requiring advanced mathematical competencies. To bridge the gap between formal theory and engineering applications, this article suggests an alternative instructional strategy that begins with an exposure to seven interconnected topics over one or two lectures, progressing from familiar to more complex material. These topics are revisited during the semester to reinforce understanding and contextualize applications. The sequence comprises: (i) logarithms and phasors; (ii) vector basis representation; (iii) polynomial functions; (iv) periodic functions and Fourier series; (v) Fourier transform for non-periodic functions; (vi) Laplace transform for functions not suited to Fourier analysis; and (vii) sampling and the Z -transform. By incrementally increasing conceptual complexity and leveraging visualization tools such as MATLAB, this approach demystifies transform theory and enhances students’ appreciation for the application of transforms in engineering contexts. The article offers a valuable resource for students, instructors, and textbook authors seeking a more incremental approach to transform theory instruction.
Accurate parameter identification is essential for reliable photovoltaic (PV) modeling. Although metaheuristic algorithms have been widely used for this task, many methods still suffer from slow convergence and suboptimal solutions. To improve both accuracy and efficiency, we propose a two-stage framework that combines maximum power matching (MPM) with a multistrategy enhanced northern goshawk optimization (MSENGO) algorithm. First, the measured current–voltage ( I – V ) data are preprocessed to remove outliers and reduce redundancy. Next, MPM provides initial parameter estimates, which are then refined by MSENGO. MSENGO incorporates three complementary mechanisms: tent-chaotic initialization for enhancing population diversity, a wavelet-based mutation operator for intensified local refinement, and a nonlinear time-varying coordination schedule (sine-decreasing and cosine-increasing) to adaptively regulate the exploration–exploitation trade-off. On the CEC2017 benchmark set (F1–F12), MSENGO attains the theoretical optimum on 11 out of 12 functions and exhibits faster convergence than the compared optimizers. For PV parameter identification under three irradiance levels (379, 590, and 900 W/m 2 ), MSENGO achieves root mean square error (RMSE) values of 0.00717, 0.00655, and 0.00651 A, respectively, with R 2 = 0.9999 in all cases and computation times of 12.15–13.02 s. Compared with the best baseline method in each irradiance case, the RMSE reduction reaches approximately 12–48%, demonstrating clear accuracy and efficiency advantages. The proposed framework also maintains competitive performance when extended to more complex PV models (double-diode model and triple-diode model), indicating good generality.
Circuit analysis is essential for studying other more specialized areas of electrical engineering. Traditional tools of analysis include the mesh current method and the node voltage method; however, neither approach is universally applicable to all circuit configurations. In this work, we introduce the node-impedance method as a comprehensive framework for electric circuit analysis. This method serves as an effective alternative to classical techniques and, in many practical situations, offers a more straightforward implementation. The node-impedance method is applicable to all types of circuits without additional steps. By knowing in advance the transfer gain between nodes, the method facilitates the systematic construction of the signal-flow graph. The proposed method can be used to solve simple and complex circuits, calculate transfer functions, and solve feedback circuits containing one or more loops. From a pedagogical perspective, the node-impedance method is particularly valuable, as it provides insight into the circuit topology uncovers non-obvious interconnections between nodes, and reveals hidden feedback loops.
This study examines Uganda's photovoltaic solar power generation and transmission situation in order to evaluate technical performance, capacity installation, economic viability, and environmental benefits. Solar energy is consistently underutilized in Uganda's energy mix despite the country's equatorial location and high solar irradiation of 5.1 to 6.5 kWh/m 2 /day. The study uses a methodical review method based on peer-reviewed literature, national energy reports, mathematical generation and transmission models, and policy documents that evaluate photovoltaic (PV) capacity trends, transmission losses, investment significance, levelized cost of energy (LCOE), and CO 2 emission reductions. Consequently, the findings show Uganda's installed grid-connected solar capacity increased from 51.8 MW in 2019 to 88.4 MW in 2024. Kabulasoke (20 MW), Soroti (10 MW), Tororo (10 MW), Mayuge (10 MW), and Busitema (4 MW) are major installations that are mainly found in high-irradiance eastern and central regions that border eastern Uganda. These systems help cover loads in both off-grid and grid-connected areas, but they are limited by transmission inefficiencies, which are mostly caused by ohmic and corona losses and aging 132 kV lines. As climate change costs from CO 2 emissions are included in LCOE analysis, PV systems become more competitive due to economic assessment, and installing solar panels offers quantified carbon emission reductions as compared to biomass-based hydropower generation. The study's conclusions suggest that Uganda has substantial technological and economical potential for the expansion of solar power; nevertheless, economic gaps, a lack of energy storage facilities, and transmission challenges limit optimal performance. The implementation of hybrid PV-storage systems, the strengthening of transmission infrastructure, and the introduction of certain regulatory incentives are all essential for improving energy security, minimizing emissions, and promoting sustainable development.
Aerospace vehicles undergo rigorous qualification tests to protect against lightning strikes. The military standard recommends subjecting test specimens to three specific high-voltage waveforms (types A, B and D). A comprehensive study analyses these waveforms regarding their energy content. Utilising experimentally obtained breakdown voltages (BDV) from the published literature, the magnitude of energy for specific time durations was computed for these waveforms in the present study. Type D exhibits the highest magnitude of energy, while its BDV is the lowest. The plot of the reciprocal of energies against their specific time durations resembles V-t characteristics of a typical insulation configuration. The magnitude of energy computed using equal voltage-peak for simulated waveforms exhibits a trend resembling the experimental results. Similarly, the computed voltage-peaks of these waveforms with equal energy are plotted as a function of time durations and resemble the experimentally obtained V-t characteristics. A waveform with higher energy content requires lower voltage-peaks from the breakdown point of view. This observation would help determine the voltage test magnitudes for the test waveforms specified in the military standard. This energy-based comparison, probably attempted for the first time, could lead to a critical evaluation and understanding of these test waveforms.
The increasing reliance on grid-connected photovoltaic (PV) systems for sustainable energy underscores the need for effective fault diagnosis to ensure system reliability and performance. This paper proposes a novel methodology that transforms multi-channel one-dimensional time series signals from PV systems into two-dimensional images, enabling feature extraction using a pre-trained MobileNetV1 network. We evaluate various classifiers, including gradient boosting, K-nearest neighbors, support vector machine, and a proposed voting classifier (VCL) that combines these models to improve accuracy and robustness. The dataset comprises 1,800 images across three classes: healthy systems, inverter faults, and grid anomalies, including tests on noisy and unbalanced data distributions to assess practical applicability. Experimental results show that the VCL outperforms individual classifiers and existing state-of-the-art methods, achieving high performance across all metrics with an overall accuracy of 99.81%. These findings demonstrate the effectiveness of the proposed approach for reliable and robust PV system fault diagnosis.
STRING is an important concept in geometry and physics, and is closely related to the distribution of energy system. This paper finds a geometric phenomenon that some properties of two-dimension STRING also exists in multiple-dimension STRING and proposes a STRING theorem from a dimension to high dimension. On this basis, an algorithm is designed to demonstrate the theorem and verify it. The concept of quantum energy density function is established to reveal the energy density conversion rule, and change trend between low-dimensional space and high-dimensional space in the framework of string theory.
The advent of the Internet era has brought tremendous changes to people's way of life and work, and its convenience and efficiency have promoted the rapid development of the society. However, the openness and dissemination of the Internet also have some negative effects, especially for ideological and political education in colleges and universities, its negative effects are quite significant. Through ideological and political education, students can correct learning attitude, cultivate good ideological and moral character, guide students to establish the correct values, outlook on life, moral values. How to carry out effective innovation of ideological and political education in colleges and universities in the network era and realize the advancement of ideological and political education has become a major problem facing colleges and universities at present. This paper makes a special study on the innovative strategies of ideological and political education methods in colleges and universities in the network era.
This paper develops a time-varying model for battery tabs based on the parametric excitation of Euler-Bernoulli beams. The instability caused by combination resonance under a high-frequency longitudinal load is considered. A Galerkin procedure is used to discretize the time-dependent problem into the Mathieu equation. The critical axial load is obtained from the transition curve of combination resonance. The effectiveness of the stability analysis was verified by numerical simulations involving longitudinal and bending loads.
Wireless technologies have become the model for Entertainment, Communication and Education all over the world. Electrical and Electronics Engineering Departments of various Universities across the globe offer courses on Wireless Communication and Networks for Undergraduate and Postgraduate students by focusing on the latest teaching pedagogy. Recent advancements in health care services demand reliable transmission of medical images and videos for better diagnosis and treatment. The effective utilization of available spectrum is one of the requirements for stable transmission of medical information. A Long Term Evolution (LTE) system model for a real-time multimedia application must provide high Quality of Service (QoS). Scheduling and allocating resources for real-time downlink flows in LTE networks is a challenging issue, as the network excellence and assured output have to be confirmed together with decreasing the Head of Line (HOL) suspension. The ever increasing demand for higher data rates in uplink and downlink transmission services constraints on delay and bandwidth requirements. This leads the existing fourth generation LTE wireless networks to concentrate more on the resource scheduling techniques with acceptable levels of Quality of Service (QoS). In this paper, a Game theory based scheduling (GTBS) and resource allocation Algorithm multimedia traffic in LTE network is designed and studied. The Algorithm is simulated in LTE-sim for real time (RT) and Non-real time (NRT) data traffic. The work identified a new teaching pedagogy, the work is explained to the undergraduate Engineering students so that they can apply the knowledge to develop new innovative projects.
Classroom teaching tact is a kind of sensitive, rapid and accurate judgment and response ability of teachers in the face of complex classroom teaching situations. The implementation of the new curriculum reform requires teachers to have a higher level of teaching tact. Based on the self-designed questionnaire, this study investigated 200 primary school students in Hunan Normal University, explored the main influencing factors of their classroom teaching tact, and verified the rationality, reliability and validity of the questionnaire structure. It is found that the differences of gender and major have no influence on the level of classroom teaching tact of primary school students on post internship, while the differences of professional identity, personality, teaching class size, teaching reflection and post job training will bring the differences of classroom teaching tact level of primary school students on post internship. The primary school students who have high degree of professional identity, outgoing personality, small class size, good teaching reflection and more job-related classroom teaching and training have higher level of classroom teaching wit. But at the same time, we should also consider the interaction of various factors and do a holistic and dialectical thinking on the analysis of the factors that affect the level of classroom teaching tact of primary school students.
Building information modeling (BIM) is another revolutionary computer application technology after computer aided design (CAD). And it's developing rapidly. At the same time, it is considered to be a technology that can overcome many problems in the construction industry, such as low production efficiency and waste of resources. In this paper, through consulting a large number of materials, combined with the research results at home and abroad, we introduced the discovery learning theory, combined with literature review method, experience summary method and case study method to establish a BIM course teaching scheme research model for application-oriented talents training, and carried out research on BIM teaching scheme in China, and analyzed and summarized the traditional teaching design The results show that the overall efficiency of BIM teaching scheme research is improved by 20%, and the efficiency is higher, which has certain practical value.
This manuscript presents a new experimental wind generator based on piezoelectric energy conversion for low power applications. The aim is to demonstrate an alternative renewable energy generation method for low power applications. The generator has four blades of a propeller equipped with a total of twenty-four (24) thin film piezoelectric transducers (TFPTs). The output voltage is generated using a newly developed circuit topology. The generator was tested at three wind speeds 10 m/s, 14 m/s and 18 m/s, with a maximum output voltage of 10.2 V being produced at a wind speed of 18 m/s. Results show that this generator has promise to be suitable for low power batteryless applications, for example wireless sensor nodes (WSN).
The family education responsibilities of rural left-behind children are not fully implemented, and school education is weak, which has caused a series of problems. The education of rural left-behind children has gradually attracted people's attention. In this context, this article studies the current situation and countermeasures of rural LBC education and teaching. This article combines research methods such as questionnaire survey method and on-site interview method for research. In order to better explain the problems of local government, this article first defines the definition of local government, expounds the theory of personality development, and uses scientific sampling methods in the research process to extract research results from some rural areas in our province.了Analysis. Based on the performance of LBC and non-LBC schools, learning guidance and learning, the current situation of LBC education in China was studied. In addition, this article also studied the performance of LBC parents before and after they went abroad, and made some suggestions. The study found that before the parents went out, LBC's academic performance was mainly concentrated at the intermediate level and above, accounting for 78%. After the parents went out, LBC's academic performance decreased significantly, and the results were mainly concentrated in the intermediate and above. Below, accounting for 84%. It can be seen that the role of parents in children's growth education is essential.
