Ferroresonance is an oscillation in a power network having a capacitor and a saturable transformer linked to a light load or no load. Stability of the ferroresonance circuit and its dependency on the different circuit parameters are the key concerns to understand its behaviour. As the internal structure of a transformer is non-homogeneous and the system equation is also nonlinear, the nonlinear dynamic method is considered the best method to solve the problem. A nonlinear equation is used to describe the nonlinear behaviour of the transformer's core material when there is no load. The power network's capacitive effects are regarded as a capacitor connected in series with the equivalent circuit of the transformer. To validate the model, ferroresonance was first established in a laboratory experiment. The parameters thus obtained from the experiment are used in the simulation. The line capacitance is taken as the variable parameter in the simulation. The stability of the ferroresonance circuit was examined with the variation of capacitor values. The Poincaré map is used to understand the change in the stability behaviour of the system. Although many analytical methods have been attempted to explain the ferroresonance oscillation, the change in stability of the system dynamics with the line capacitance has not been demonstrated in any previous literature.
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.
