Electrical & Electronics Engineering

Permanent URI for this collectionhttp://197.211.34.35:4000/handle/123456789/130

Electrical & Electronics Engineering

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Start date: 2010End date: 2019

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Now showing 1 - 10 of 11
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    EFFECTS OF UNIFIED POWER FLOW CONTROLLER (UPFC) ON DISTANCE RELAY TRIPPING CHARACTERISTICS IN THE NORTH-CENTRAL NIGERIAN 330kV NETWORK
    (Nigerian Journal of Technology (NIJOTECH), 2015-10) Yusuf, Latifa
    This paper investigates the effects of UPFC on Distance Relay tripping characteristics in the Nigerian 330kV (North-Central) Network. Its operation is based on impedance measurement at the relaying point. However, the system performance is often impeded by certain operational or structural factors such as load angle, the voltage magnitude ratio at the line ends, pre-fault line loading, and short circuit levels at the line ends. The Unified Power Flow controllers (UPFC) incorporated into the Nigerian 330kV (North-Central) Network were modelled in the environment of Power System Computer Aided Design (PSCAD) and kept within the protected zone of the relay to increase the Apparent Resistance, causing the relay to malfunction. Therefore, it is deduced by simulation analysis that the presence of UPFC in a faulted transmission line loop, protected by distance relay, greatly affects the trip boundaries of the distance relay by setting it to either an over-reaching or an under-reaching state. Hence, the tripping characteristics of distance relay with UPFC located at various points with respect to a fault on a transmission line culminated in three scenarios, the results of which are presented and discussed in this paper.
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    Analysis of Double Salient Reluctance Machine Using Total Surface Gap Area
    (2nd International Engineering Conference (IEC2017) Federal University of Technology, Minna, Nigeria, 2017-06-12) Enesi, A. Y; Ejiogu, E. C; Anih, L. U
    In this paper, we analyze the stator-rotor design of a double salient reluctance machine using total surface gap area. The high number of poles in a 4-phase reluctance machine makes it suitable for the analysis. An expression is derived for the total surface gap area which includes the sum of the area of the air-gap (between the inner stator radius and the outer rotor radius), the area between the gaps of the stator poles and the area between the gaps of the rotor poles. The rated torque and the rated power output are expressed through the total surface gap area and the geometrical parameters. The total surface gap area is used to predict the torque ripple and the average torque developed by the machine for different pole arcs, air gaps, number of poles, number of phases and frequencies which are investigated by MATLAB simulation. The stator and the rotor of the machine are drawn by ANSYS software for the purpose of visualization.
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    Parametric osicillations in electric oscillatory system
    (3rd International Engineering Conference (IEC2019), Federal University of Technology, Minna, Nigeria, 2019-06-12) Enesi A.Y; Ejiogu E.C
    The paper presents the parametric oscillations generated in an electric oscillatory system. Parametric oscillations are oscillations that are periodically modulated with time. The modulation depth and the carrier frequency are investigated by MATLAB/Simulink Model developed from Mathieu's equation. With this model, parametric oscillations are generated. The maximum and minimum amplitudes of oscillations for each characteristic number, a and the characteristic parameter, q is determined. The time taken for one oscillation (which is the period) for each characteristic number and characteristics perameter is determined. The relationship between the carrier frequency, the modulation depth and the characteristic number are established through graphical illustrations. These are approximate results of the solutions of Mathieu equation in electric oscillatory system.
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    Performance Analysis of Data Normalization Methods
    (International Engineering Conference 2017, 2017-10-17) Ajiboye, Johnson Adegbenga; Aibinu M.A
    Statistical Data Normalization is a very important input preprocessing operation that should be done before data is fed into the training network. However, there is need for a suitable selection of normalization technique since normalization on the input has potential of varying the structure of the data and may impact on the outcome of the analysis. This paper investigates and evaluates some important statistical normalization techniques by studying thirty published papers that used wine dataset available in the UCI repository and their impact on performance accuracy. Results reveal that Min-Max normalization technique had the best performance accuracy of 95.91% on the average among all the other normalization types.
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    Performance Analysis of Statistical Time Division Multiplexing Systems
    (Leonardo Electronic Journal of Practices and Technologies, 2010) Ajiboye, Johnson Adegbenga; Yinusa Ademola Adediran
    Multiplexing is a way of accommodating many input sources of a low capacity over a high capacity outgoing channel. Statistical Time Division Multiplexing (STDM) is a technique that allows the number of users to be multiplexed over the channel more than the channel can afford. The STDM normally exploits unused time slots by the non-active users and allocates those slots for the active users. Therefore STDM is appropriate for bursty sources. In this way STDM normally utilizes channel bandwidth better than traditional Time Division Multiplexing (TDM). In this work, the statistical multiplexer is viewed as M/M/1queuing system and the performance is measured by comparing analytical results to simulation results using Matlab. The index used to determine the performance of the statistical multiplexer is the number of packets both in the system and the queue. Comparison of analytical results was also done between M/M/1 and M/M/2 and also between M/M/1 and M/D/1 queue systems. At high utilizations, M/M/2 performs better than M/M/1. M/D/1 also outperforms M/M1.
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    Pattern and Feeder Design for the Production of Grey Cast Iron Brackets
    (IUP Journal of Mechanical Engineering, 2013-08-01) Mary Adebola Ajiboye; Matthew Sunday Abolarin; Ajiboye, Johnson Adegbenga
    In this paper, the design and production of sand casting for a gray cast iron bracket was carried out. The bracket was divided into different sections called Appendages A,B,C and D, and Ribs E and F. Efficient feeder design is important so as to minimize casting defects such as porosity and incomplete filling to the barest minimum. The feeder or riser is used to feed metal to the casting as it solidifies; therefore, they are designed and positioned such as to ensure filling the cavity during solidification. The implication of this is that the riser must be designed to be large enough so that it solidifies only after the casting and it should contain a sufficient volume of metal capable of supplying the shrinkage contraction which occurs on cooling from the casting temperature to the completion of solidification. Based on the feeder design in this work, two bracket castings were produced.
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    Design and Implementation of a 5 kVA Inverter
    (IUP Journal of Electrical and Electronic Engineering, 2016-10-01) Ajiboye, Johnson Adegbenga; Chukwuka Anene; Mary Adebola Ajiboye; Abraham U. Usman
    The paper describes the design and construction of a 5 kVA Pulse Width Modulated (PWM) Metal Oxide Semiconductor Field Effect Transistor (MOSFET)-based inverter, which works on the principle of PWM. The inverter uses IC SG3524 and a pair of Twelve MOSFETs to drive the load. The design and implementation starts with the power supply. Component selection was made with the aid of electronics data book, which made the design and calculations very easy. One main feature of this inverter is the monitoring section, and the battery-charging section connected to the inverter circuit. The inverter converts DC supply of the battery into AC power supply required by most electrical appliances/equipment when the AC main is not available; and when the AC main is available, the supply goes to the AC main sensor, the relays and battery charging section of the inverter. This inverter can be used for domestic purpose, and it is not recommended for industrial purpose where high current is required for application, such as starting a heavy-duty motor
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    Secrecy Rate Optimizations for MIMO Communication Radar
    (IEEE, 2018-03-28) Anastasios Deligiannis; Abdullahi Daniyan; Sangarapillai Lambotharan; Jonathon A. Chambers
    In this paper, we investigate transmit beampattern optimization techniques for a multiple-input multiple-output radar in the presence of a legitimate communications receiver and an eavesdropping target. The primary objectives of the radar are to satisfy a certain target-detection criterion and to simultaneously communicate safely with a legitimate receiver by maximizing the secrecy rate against the eavesdropping target. Therefore, we consider three optimization problems, namely target return signal-to-interference-plus-noise ratio maximization, secrecy rate maximization, and transmit power minimization. However, these problems are nonconvex due to the nonconcavity of the secrecy rate function, which appears in all three optimizations either as the objective function or as a constraint. To solve this issue, we use Taylor series approximation of the nonconvex elements through an iterative algorithm, which recasts the problem as a convex problem. Two transmit covariance matrices are designed to detect the target and convey the information safely to the communication receiver. Simulation results are presented to validate the efficiency of the aforementioned optimizations.
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    Kalman-Gain Aided Particle PHD Filter for Multitarget Tracking
    (IEEE, 2017-04-05) Abdullahi Daniyan; Yu Gong; Sangarapillai Lambotharan; Pengming Feng; Jonathon Chambers
    We propose an efficient sequential Monte Carlo probability hypothesis density (PHD) filter which employs the Kalman-gain approach during weight update to correct predicted particle states by minimizing the mean square error between the estimated measurement and the actual measurement received at a given time in order to arrive at a more accurate posterior. This technique identifies and selects those particles belonging to a particular target from a given PHD for state correction during weight computation. Besides the improved tracking accuracy, fewer particles are required in the proposed approach. Simulation results confirm the improved tracking performance when evaluated with different measures.
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    Bayesian Multiple Extended Target Tracking Using Labeled Random Finite Sets and Splines
    (IEEE, 2018-10-04) Abdullahi Daniyan; Sangarapillai Lambotharan; Anastasios Deligiannis; Yu Gong; Wen-Hua Chen
    In this paper, we propose a technique for the joint tracking and labeling of multiple extended targets. To achieve multiple extended target tracking using this technique, models for the target measurement rate, kinematic component, and target extension are defined and jointly propagated in time under the generalized labeled multi-Bernoulli filter framework. In particular, we developed a Poisson mixture variational Bayesian model to simultaneously estimate the measurement rate of multiple extended targets and extended target extension was modeled using B-splines. We evaluated our proposed method with various performance metrics. Results demonstrate the effectiveness of our approach.