<abstract><title style='display:none'>Abstract</title> This paper presents results of study of loss-of-excitation phenomena simulations. Loss of excitation is a very common fault in synchronous machine operating and can be caused by short circuit of the field winding, unexpected field breaker open or loss-of-excitation relay mal-operation. According to the statistic [1], the generator failure due to loss-of-excitation accounts for 69% of all generator failures. There has been concern over possible incorrect operation of the relay when operating the generator in the under-excited region, during stable transient swings and during major system disturbances. This article can serve as inputs for system operators in preparation of operation area or protection relaying area.</abstract>

Power System Management s.r.o., Ondavská 5, 040 01 Košice,

Vchodoslovenská distribučná, a.s., Mlynská 31, 040 01 Košice,

Loss of excitation of synchronous generator

<abstract xml:lang="en"><title style='display:none'>Voice Conversion Using Pitch Shifting Algorithm by Time Stretching with PSOLA and Re-Sampling</title>Voice changing has many applications in the industry and commercial filed. This paper emphasizes voice conversion using a pitch shifting method which depends on detecting the pitch of the signal (fundamental frequency) using Simplified Inverse Filter Tracking (SIFT) and changing it according to the target pitch period using time stretching with Pitch Synchronous Over Lap Add Algorithm (PSOLA), then resampling the signal in order to have the same play rate. The same study was performed to see the effect of voice conversion when some Arabic speech signal is considered. Treatment of certain Arabic voiced vowels and the conversion between male and female speech has shown some expansion or compression in the resulting speech. Comparison in terms of pitch shifting is presented here. Analysis was performed for a single frame and a full segmentation of speech.</abstract>

Voice Conversion Using Pitch Shifting Algorithm by Time Stretching with PSOLA and Re-Sampling

<abstract xml:lang="en"><title style='display:none'>Single Phase PWM Rectifier in Traction Application</title>This research has been motivated by industrial demand for single phase PWM rectifier in traction application. This paper presents an advanced control structure design for a single phase PWM rectifier. The PWM rectifier is controlled to consume nearly sinusoidal current with power factor nearing to unity. The control structure consists of a DC-link voltage controller and a current controller implemented by a proportional-resonant controller using a fast phase angle and frequency estimator. The estimation algorithm is derived from the weighted least-squares estimation method. The feasibility of the proposed control structure is confirmed by experimental tests performed on designed laboratory prototype.</abstract>

Single Phase PWM Rectifier in Traction Application

<abstract xml:lang="en"><title style='display:none'>A New Soft Starting Method for Wound-Rotor Induction Motor</title>Starting of a three-phase Induction motor using a starter rheostat in rotor circuit has some disadvantages. A new method for starting of a three-phase motor by using a parallel combination of resistors, self-inductors and capacitors in rotor circuit is proposed in this paper. The proposed method ensures the soft and higher starting torque as well as limited starting current as compared to shorted rotor method. The characteristic curves for both methods (shorted rotor and rotor with added elements) are provided. The mathematical model based on the steady-state equivalent circuit of the induction motor is expanded in frequency domain and the required computer program is prepared using an optimization method. The values for added elements to rotor circuit are calculated in such a way that minimum starting time considering current and torque limitations are achieved.</abstract>

A New Soft Starting Method for Wound-Rotor Induction Motor

<abstract>The purpose of this paper is to present the design and program implementation of a general procedure which yields the mathematical model for a classical or rotary inverted pendulum system with an arbitrary number of pendulum links. Lagrange equations of the second kind with an integrated Rayleigh dissipation function are employed in model design, and the energetic balance relations, derived for the base and all pendulum links in a generalized (n-link) classical and rotary inverted pendulum system, are implemented in form of symbolic MATLAB functions and a MATLAB GUI application. The validity and accuracy of motion equations generated by the application are demonstrated by evaluating the open-loop responses of simulation models of classical double and rotary single inverted pendulum.</abstract>

Modelling of Classical and Rotary Inverted Pendulum Systems – A Generalized Approach

<abstract xml:lang="en"><title style='display:none'>Understanding Electrical Treeing Phenomena in XLPE Cable Insulation Adopting UHF Technique</title>A major cause for failure of underground cables is due to formation of electrical trees in the cable insulation. A variety of tree structure can form from a defect site in cable insulation <italic>viz</italic> bush-type trees, tree-like trees, fibrillar type trees, intrinsic type, depending on the applied voltage. Weibull studies indicate that a higher applied voltage enhances the rate of tree propagation thereby reducing the life of cable insulation. Measurements of injected current during tree propagation indicates that the rise time and fall time of the signal is of few nano seconds. In the present study, an attempt has been made to identify the partial discharges caused due to inception and propagation of electrical trees adopting UHF technique. It is realized that UHF signal generated during tree growth have signal bandwidth in the range of 0.5-2.0 GHz. The formation of streamer type discharge and Townsend type discharges during tree inception and propagation alters the shape of the tree formed. The UHF signal generated due to partial discharges formed during tree growth were analyzed adopting Ternary plot, which can allow one to classify the shape of tree structure formed.</abstract>

Department of Electrical Engineering, IIT Madras, Chennai-600 036, India

Department of Electrical and Computer Engineering, Democritus University of Thrace, Xanthi, Greece

Understanding Electrical Treeing Phenomena in XLPE Cable Insulation Adopting UHF Technique

<abstract>
<title style='display:none'>Abstract</title>
The designed circuit features a dual-stage Low Noise Amplifier (LNA) in which, a common source (CS) configuration is employed to achieve high gain, while the subsequent stage adopts a Complementary Common Gate (CCG) setup provide the low power consumption. This arrangement ensures that both transistors share the same biasing current, promoting energy efficiency. The two stages are interconnected in a cascade configuration, amplifying the overall gain and concurrently mitigating noise. To facilitate wideband matching in the input stage, a parallel RC feedback mechanism is implemented. Additionally, a pair of mutually coupled inductors in the CS and CCG stages contribute to rendering the input impedance exclusively resistive, concurrently minimizing the overall size of the circuit. All simulations were done using 65 nm CMOS technology in Cadence Virtuoso. The proposed LNA showcases a Noise Figure (NF) of 3.2 dB, a Peak Power Gain (<italic>S</italic>21) of 19.8 dB, and an input reflection coefficient (<italic>S</italic>11) of –16.2 dB, spanning a bandwidth of 3.1-6.2 GHz. Operating on a 1V power supply, the proposed LNA demonstrates power efficiency by consuming only 2.8 mW. The overall performance assessment of the LNA is gauged using the Figure of Merit, yielding an obtained value of 18.2. Comparative analysis with other cutting-edge designs is presented in Table 1.
</abstract>

Mutually coupled dual-stage RC feedback LNA for RF applications

<abstract>
<title style='display:none'>Abstract</title>
This study presents the crucial parts of the final construction of a combined temperature meter with wireless transmission of temperature data. The wireless transmission of temperature information is realized by optical coupling between the photodiode and the phototransistor through the air, not through an optical fibre. The power source is structurally unique in that its output terminals have mechanical freedom and thus the possibility to rotate without using mechanical contacts. Transmission of the supply energy is mediated by the magnetic field in a pot core transformer. A linear symmetrical post-regulator stabilizing the output voltage and ensuring the symmetry of the output voltages is included at the output of the source.
</abstract>

Construction and characteristics of a thermometer in a hot filament CVD reactor for synthesis of nanocomposites based on carbon nanotubes

<abstract>
<title style='display:none'>Abstract</title>
Despite the widespread adoption of the Routing Protocol for Low-power and Lossy Networks (RPL) in IoT environments, its inherent limitations in addressing security vulnerabilities have left IoT networks vulnerable to ongoing attacks. This paper introduces a novel intrusion detection system tailored specifically for IoT networks, with a focus on mitigating attacks at the network’s edge. The study presents the Hybrid Rank Attack (HRA), a sophisticated threat exploiting RPL vulnerabilities by alternately advertising decreased and increased rank values in control messages. Extensive experimentation evaluates the detrimental effects of HRA on critical network metrics including exchanged messages, energy consumption, PDR, latency, and memory footprint. Additionally, a lightweight and distributed countermeasure algorithm is proposed to effectively mitigate the impact of HRA. Simulation-based evaluations demonstrate significant reductions in control overhead (68.7%) and energy consumption (61.83%), with minimal additional RAM utilization (1.05%). This lightweight solution enhances the resilience of RPL-based IoT networks against HRA threats.
</abstract>

Exploring and mitigating hybrid rank attack in RPL-based IoT networks

<abstract>
<title style='display:none'>Abstract</title>
The current research is dedicated to harnessing cutting-edge technologies within the paradigm of Industry 5.0. The objective is to capitalize on advancements in Machine and Deep Learning techniques. This research endeavors to construct robust predictive models, utilizing historical data, for precise real-time predictions in estimating material quantities within a cement workshop. Machine Learning regressors evaluated based on several metrics, SVR (R-squared 0.9739, MAE 0.0403), Random Forest (R-squared 0.9990, MAE 0.0026), MLP (R-squared 0.9890, MAE 0.0255), Gradient Boosting (R-squared 0.9989, MAE 0.0042). The time series models LSTM and GRU yielded R-squared 0.9978, MAE 0.0100, and R-squared 0.9980, MAE 0.0099, respectively. The ultimate outcomes include improved and efficient production, optimization of production processes, streamlined operations, reduced downtime, mitigation of potential disruptions, and the facilitation of the factory’s evolution towards intelligent manufacturing processes embedded within the framework of Industry 5.0. These achievements underscore the potential impact of leveraging advanced machine learning techniques for enhancing the operational dynamics and overall efficiency of manufacturing facilities
</abstract>

Forecasting material quantity using machine learning and times series techniques

<abstract>
<title style='display:none'>Abstract</title>
The Hamming code or Linear block code is used in communication to identify and repair errors. Redundancy bits are introduced to the Hamming communication network (HCN) for error detection and correction. It can detect two errors and correct one error. Quantum-dot Cellular Automata (QCA) is used for designing circuits with high switching speed and low energy dissipation. This work proposes a cost-effective QCA-based (7, 4) Hamming encoder and decoder design. Hamming encoder is designed using coplanar structure and the error detector used in Hamming decoder uses a multilayer structure. The effort is to optimize the area, cost, and energy dissipation. The work proposes a coplanar (7, 4) Hamming encoder and decoder. Hamming decoder is implemented in two parts a syndrome calculator and an error detector. Proposed (7, 4) Hamming encoder circuit reduces cell count by 49.47% compared to [<xref ref-type="bibr" rid="j_jee-2024-0028_ref_001">1</xref>] and 9.52% compared to [<xref ref-type="bibr" rid="j_jee-2024-0028_ref_012">12</xref>]. The proposed (7, 4) syndrome calculator has reduced cell count by 56.54%, an 11.11% reduction in total area compared to [<xref ref-type="bibr" rid="j_jee-2024-0028_ref_001">1</xref>]. The proposed design reduces the cell area, QCA cost, and also energy dissipation. The designs are realized and QCA parameters are assessed in QCADesigner2.0.3 and energy is analyzed in QCADesigner-E.
</abstract>

Area and energy optimized Hamming encoder and decoder for nano-communication

<abstract>
<title style='display:none'>Abstract</title>
This paper presents an artificial neural network (ANN) based method for overhead lines magnetic flux density estimation. The considered method enables magnetic flux density estimation for arbitrary configurations and load conditions for single-circuit, multi-circuit, and also overhead lines that share a common corridor. The presented method is based on the ANN model that has been developed using the training dataset that is produced by a specifically designed algorithm. This paper aims to demonstrate a systematic and comprehensive ANN-based method for simple and effective overhead lines magnetic flux density estimation. The presented method is extensively validated by utilizing experimental field measurements as well as the most commonly used calculation method (Biot - Savart law based method). In order to facilitate extensive validation of the considered method, numerous magnetic flux density measurements are conducted in the vicinity of different overhead line configurations. The validation results demonstrate that the used method provides satisfactory results. Thus, it could be reliably used for new overhead lines’ design optimization, as well as for legally prescribed magnetic flux density level evaluation for existing overhead lines.
</abstract>

Artificial neural network-based method for overhead lines magnetic flux density estimation

<abstract xml:lang="en"><title style='display:none'>Small-Signal Analysis of Autonomous Hybrid Distributed Generation Systems in Presence of Ultracapacitor and Tie-Line Operation</title>This paper presents small-signal analysis of isolated as well as interconnected autonomous hybrid distributed generation system for sudden variation in load demand, wind speed and solar radiation. The hybrid systems comprise of different renewable energy resources such as wind, photovoltaic (PV) fuel cell (FC) and diesel engine generator (DEG) along with the energy storage devices such as flywheel energy storage system (FESS) and battery energy storage system (BESS). Further ultracapacitors (UC) as an alternative energy storage element and interconnection of hybrid systems through tie-line is incorporated into the system for improved performance. A comparative assessment of deviation of frequency profile for different hybrid systems in the presence of different storage system combinations is carried out graphically as well as in terms of the performance index (PI), <italic>ie</italic> integral square error (ISE). Both qualitative and quantitative analysis reflects the improvements of the deviation in frequency profiles in the presence of the ultracapacitors (UC) as compared to other energy storage elements.</abstract>

Research Scholar, Department of Electrical Engineering, Motilal Nehru National Institute of Technology, Allahabad, India

Department of Electrical Engineering, Motilal Nehru National Institute of Technology, Allahabad, India

Small-Signal Analysis of Autonomous Hybrid Distributed Generation Systems in Presence of Ultracapacitor and Tie-Line Operation

<abstract><title style='display:none'>Abstract</title> This paper investigates the hybrid chaos synchronization of identical Wang four-scroll systems (Wang, 2009), identical Liu-Chen four-scroll systems (Liu and Chen, 2004) and non-identical Wang and Liu-Chen four-scroll systems. Active control method is the method adopted to achieve the hybrid chaos synchronization of the four-scroll chaotic systems addressed in this paper and our synchronization results are established using Lyapunov stability theory. Since the Lyapunov exponents are not required for these calculations, the active control method is effective and convenient to hybrid synchronize identical and different Wang and Liu-Chen four-scroll chaotic systems. Numerical simulations are also shown to illustrate and validate the hybrid synchronization results derived in this paper.</abstract>

Department of ECE, Velammal Institute of Technology, Panchetti, Tiruvalluvar District, India

Research and Development Centre, Vel Tech Dr. RR & Dr. SR Technical University, Avadi, Chennai-600 062, India

Hybrid Chaos Synchronization of Four–Scroll Systems via Active Control

<abstract xml:lang="en"><title style='display:none'>Optimal Relays Coordination Efficient Method in Interconnected Power Systems</title>In this paper an efficient method for optimal overcurrent relay coordination is proposed. In the proposed method using genetic algorithm, an objective function (OF) is developed to solve the problem of miscoordination for six pairs short circuit fault currents. The new OF is improved to be simple, optimal and efficient. This technique takes into account the changes in network configuration. The efficiency of the proposed technique is demonstrated by comparing the results of two different networks namely typical 8-bus &amp; IEEE 30-bus systems with those obtained using the recently developed techniques.</abstract>

Center of Excelence on Power System, Amirkabir University of Technology, Iran

Optimal Relays Coordination Efficient Method in Interconnected Power Systems

<abstract><title style='display:none'>Abstract</title>This paper presents a tuning approach based on Continuous firefly algorithm (CFA) to obtain the proportional-integral- derivative (PID) controller parameters in Automatic Voltage Regulator system (AVR). In the tuning processes the CFA is iterated to reach the optimal or the near optimal of PID controller parameters when the main goal is to improve the AVR step response characteristics. Conducted simulations show the effectiveness and the efficiency of the proposed approach. Furthermore the proposed approach can improve the dynamic of the AVR system. Compared with particle swarm optimization (PSO), the new CFA tuning method has better control system performance in terms of time domain specifications and set-point tracking.</abstract>

CONTINUOUS FIREFLY ALGORITHM FOR OPTIMAL TUNING OF PID CONTROLLER IN AVR SYSTEM

<abstract>This paper deals with certain options on controlling an inverted rotary pendulum also known as the Furuta pendulum. Controlling an inverted pendulum involves two stages. The first stage is the swing up of the pendulum and the second stage is its balancing in the up-right position. The paper describes two possibilities on swinging up the pendulum. First one is the classical approach based on comparing the current total (potential and kinetic) energy of the system with the energy in its stabilized up-right position. The second option uses an exponentiation operation over the pendulum position since the trend of power law function is very convenient for determining the amount of required energy to be delivered to the system. For the purposes of balancing the pendulum in the up-right position a predictive controller based on optimal control law with perturbation was proposed, which is an LQ controller with control signal corrections when constraints are exceeded. The results are illustrated by real-time experiments on a laboratory rotary inverted pendulum setup.</abstract>

Swinging up the Furuta Pendulum and its Stabilization Via Model Predictive Control

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The Journal of Slovak University of Technology

 The Journal of Electrical Engineering, published bimonthly, is devoted to:   Automation and Control  Computer Engineering  Electronics,...

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The Journal of Slovak University of Technology

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