Revistas UTB ( Universidad Tecnológica de Bolívar)
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Numerical Study in Effect of Thermal Slip on Two Fluid Flow in a Vertical Channel
Full text linkThe present study investigates the effect of thermal slip on an immiscible flow of micropolar and viscous fluids in a vertical channel. The left boundary is subjected to thermal slip with appropriate boundary and interface conditions, resulting in a linked system of nonlinear partial differential equations. The ND Solve technique in Mathematica software is used to implement the Runge-Kutta method of the sixth order. The velocity, temperature, and concentration equations are then calculated. The mass, heat, and velocity transmission rates at the boundaries were recorded for all the variations in the governing parameters. In addition, the impact of relevant parameters on various physical properties of micropolar and viscous fluids is analyzed through graphical means. The results are then discussed in detail. Thermal slip, Grashof number, molecular number, magnetic parameter, and Reynolds number are crucial factors that significantly affect heat and mass transfer in fluid flow. The effect of the increased thermal slip is noted to result in a decrease in both the velocity profile and temperature. It was also observed that higher values of Grashof and molecular Grashof numbers led to increased velocity and angular velocity
Statistical Analysis to Quantify the Impact of Map Type on Estimating Peak Discharge in Non-Instrumented Basins
Full text linkThe calculation of peak discharge in non-instrumented basins requires including morphometric parameters, which in turn depend on the map type used. This study analyses the impact of and variation in peak discharges of the Caño Ricaurte basin, Colombia, based on three types of maps at different resolution scales. The reference map used was the map made for the detailed designs of the channel analysed, which was extracted from the Master Plan of the City. Additionally, maps from a 90 × 90 m digital elevation model and contour lines extracted from Google Earth were used. The time of concentration was determined by different equations (Kirpich, Témez, Bureau, and TR-55) using the mapping methods described above, and the peak discharge was determined using rainfall-runoff models
Design and Cogging Torque Reduction of Radial Flux Brushless DC Motors with Varied Permanent Magnet Pole Shapes for Electric Vehicle Application
Full text linkBrushless direct current motors have more attractive features, making them a promising solution for electric vehicle applications. A 1 kW, 510 rpm, 24-slots and 8-pole inner runner type surface permanent magnet mounted radial flux brushless DC motor with seven different permanent magnet pole shape rotor is investigated. Motors with different permanent magnet shape rotors were designed, and finite element modelling and simulation were carried out. For performance comparison, the initial design with a radial-type pole shape was regarded as a reference design. Cogging torque is detrimental to the overall performance of the motor, typically in low-speed applications like electric vehicles. The primary aim of this paper is to reduce the cogging torque & study its effect on the overall performance of the motor and minimize torque ripples with reduced permanent magnet requirements. The proposed designs are analyzed in terms of cogging torque, flux density, torque, efficiency, flux linkage and back-EMF. The comparative analysis shows that the motor with bump-shaped permanent magnet rotor poles has betterperformance than the others
Performance Enhancement of High Speed Interior Permanent Magnet Synchronous Motors Using Superior Magnetic Material
Full text linkThis paper presents the application of higher-grade magnetic material for performance improvement of interior permanent magnet synchronous motors (IPMSM) for high-speed applications. The efficiency and weight of the motor are important performance parameters for high-speed applications. Efficiency improvement with simultaneous weight reduction is the key design issue for many specific applications. The main contribution of this work is to explore the possibility of using high-grade magnetic material for efficiency improvement with a simultaneous weight reduction of IPMSM motors. Three different standard rating motors were designed with the usual M19 material, and their performance was estimated. Finite element modelling and simulation was carried out to validate the initial design. For performance comparison, initial designs were regarded as reference designs. Design improvement was carried out with the application of high-grade magnetic material Hiperco 50A and its influence on the performance of IPMSM motors was analyzed. Three different standard ratings motors were considered in this work to analyze the effect of material in a wide range. Improved design was also validated with finite element modelling and simulation. It was observed that the efficiency is effectively improved with weight reduction using Hiperco 50A material in all three standard-rating IPMSM motors
A signal conditioning module for denoising Electrocardiogram signals
Full text linkIn this work, we propose to use an optimal multiband filter with least mean square algorithm to design a signal conditioning module for denoising Electrocardiogram (ECG) signals contaminated with predominant noises. The module is implemented on a Field Programmable Gate Array (FPGA) hardware. The experimental results of the proposed module are investigated and compared using an ECGID database available on Physionet. Quantitative and qualitative analysis is performed using Signal to Noise Ratio (SNR), Mean Square Error (MSE), and quality indexes to assess the effectiveness of the module. The average values of SNR are 10.90124, and MSE is 0.001761, indicating the successful elimination of noises in the filtered ECG signal using the proposed module. The signal quality indexes also demonstrate that the relevant information for diagnosing cardiac functionality is preserved. Furthermore, the performance of the designed module is tested on ECG signals obtained from electrodes placed on the human body. The Spartan 3s500efg320-5 FPGA device is employed to implement the filter design module using the partial serial architecture
The solution of the economic dispatch problem via an efficient Teaching-Learning-Based Optimization method
Full text linkThis paper is concerned with the economic generation dispatch problem. It is a well-known fact that practical aspects of power plant equipment, as well as the objectives to be met, may result in a nonconvex, nondifferentiable model that poses difficulties to conventional mathematical programming methods. This paper proposes the use of metaheuristic Teaching-Learning-Based Optimization to overcome such difficulties. This metaheuristic is well known for requiring a few parameters and, most importantly, it does not require the tuning of problem-dependent parameters. The algorithm proposed in this work is parameter-free; that is, the few parameters required by the Teaching-Learning-Based Optimization method are set automatically based on the power system’s data. In addition, the handling of constraints, such as generators’ prohibited zones and the generator-load-loss power balance, is performed in a very efficient way. Simulation results are shown for power systems containing 3 to 40 generation units, and the results provided by the proposed method are shown and discussed based on comparisons with other metaheuristics and a mathematical programming technique
FACTS placement for reactive power planning with weak node constraints using an improved symbiotic search algorithm
Full text linkIn this paper, an economically feasible and reliable operation of the IEEE 57 bus system for Optimal Power Flow (OPF) is proposed. The Improved Symbiotic Organisms Search (ISOS) algorithm is proposed for effective reactive power planning as an OPF issue. Further, the optimal position of Flexible AC Transmission Systems (FACTS) is taken into consideration, by including the existing system controlling variables like reactive power generators output, transformer tapping and capacitors connected at shunt. The objective of the work is two-fold; i.e., to reduce the energy loss and to enhance the voltage profile within the prescribed limit by ensuring the economic operation and investment cost of FACTS in the system. In this work, two FACTS devices like Static Var Compensator (SVC) and Thyristor-Controlled Series Controller (TCSC) have been taken into consideration. Voltage sensitivity indicator and reactive power flow are two tools that are utilised in order to locate weak nodes for the implementation of FACTS. Finally, the performance of the ISOS algorithm is compared with that of three other state- of-the -art optimization techniques, such as, Symbiotic Organisms Search (SOS), Differential Evolution (DE) and Teaching Learning Based Optimization (TLBO). A Non-parametric statistical analysis is also performed to investigate the dominance of the ISOS algorithm over others
A New Weave in the Pattern
Full text linkEditor-in-Chief Andres Marrugo discusses the role of Large Language Models, like ChatGPT, in academic publishing, highlighting some practical applications, potential pitfalls, and the ethical considerations required for their responsible use in academia
Zero power mismatch islanding detection algorithm for hybrid distributed generating system
Full text linkDistributed generation is essential for both keeping up with the rising power demand and reducing the amount of money spent on fossil fuels. There is widespread agreement that the world should prioritize the development of renewable energy systems such as wind and solar energy. This study describes the design and utility-grid integration of a hybrid distributed generating system that utilizes photovoltaic and wind-driven permanent magnet synchronous generators (hybrid PMSG-PV systems). To prevent damage to the grid, hybrid distributed generation systems, consumer devices, and line workers must be protected from islanding. Detection of islanding in hybrid DG systems has been suggested using passive islanding and time-spectral analysis. Measuring and amplifying the ripple content present in voltage at point of common coupling (PCC) about 0.4 seconds after the permissible delay time after the circuit breaker opens on the utility grid side is how islanding is discovered using this method. Compared to other methods, the proposed method has smoother islanding detection waveforms owing to increases in both the window size and threshold limit. The suggested method detects islanding in 40 ms and is verified in a variety of non-islanding scenarios, such as fault occurrence, parallel feeder loss, and load shift. In addition, the cost is reduced, the response time is rapid, and there is no non-detection zone (NDZ) when using these methods. Unlike active islanding detection methods, their function is unaffected by the size, quantity, or type of distributed generators linked to the utility grid; hence, there are no power quality concerns
Analysis of Bus Vulnerability Conducted Using a Synchronized Phasor Measurement Unit in Order to Achieve the Maximum Observability
Full text linkPhasor measurement units (PMUs) have gained significant interest in recent decades. These instruments are used to measure synchronized phasor data. PMUs are gradually but definitely taking over power grids because of the significant phasor information that they generate for both regular and irregular conditions for the purpose of maintaining safety and control. PMUs may be used for a variety of purposes, including state estimation, which is a common task. In order to make state estimation more reliable, a variety of approaches have been looked into, and one of them is the positioning of PMUs. This paper provides a plan for the implementation of the PMUs, taking into account the potential for failure and vulnerability posed by PMU-equipped buses. Two separate studies were carried out and evaluated with the goal of solving the optimum PMU placement problem (OPPP), which pertains to the grids. The findings of the first study show that the maximum bus observability may be accomplished with the fewest possible number of PMUs, even while taking into consideration the fact that there is a risk that one or more PMUs would malfunction. This investigation was carried out with common measures such as zero injection bus (ZIB) and branch flow measurements, both with and without them, in order to assess the outcomes. The second research focused on selecting the PMU-equipped bus’s vulnerability analysis as its primary area of investigation. All of the tests were completed by using binary integer linear programming. Specifically, the described method is meant to be used with an existing PMU framework and in the case that new locations for new PMUs are necessary to be furnished with existing PMUs. This results confirm that the recommended strategy can be implemented successfully on the IEEE benchmark test systems