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Effect of Switching Devices on Power Quality and Transient Voltage Suppression Using Capacitor Bank Model

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Journal of Power and Energy Engineering 2022年第5期10卷 77-89页

作者： Isaac Kofi Mensah prah joseph Cudjoe Attachie Electrical and Electronic Engineering Department University of Mines and Technology Tarkwa Ghana

The main purpose of the electrical power system is to transport and distribute energy generated by the central power plants in a safe and reliable manner to the customer premises. Most of the electrical equipment is exposed within the open which suggests they can be vulnerable to lightning strikes, road dwindling, windstorms, and a few engineering activities with the potential of causing different degrees of damage to the electrical equipment. One of the ways to guard the equipment is to deploy switching devices. However, the operations of most of these switching devices produce oscillatory transient in the electrical transmission and distribution systems which result in voltage, current, and frequency fluctuations in the load. This paper investigates the effect of switching devices on power quality and proposes a positive sequence voltage power transient suppression technique that can spontaneously improve the distorted voltage at the instant of capacitor switching using the capacitor line model as a case study. MATLAB/Simulink software was utilized for the analysis on an electrical network model with bus voltages of 69 kV/12.47 kV and 480 V. The results showed that, during switching operations, the positive sequence voltage power detector block produces ripple-free accurate results.

关键词： Capacitor Banks Inrush Current Laplace Transform Power Quality Posi-tive Sequence Switching Transient Voltage

Design and Implementation of Smart Power Voltage and Frequency Synchroniser in Power Distribution System

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Journal of Power and Energy Engineering 2023年第4期11卷 1-16页

作者： Isaac Kofi Mensah prah joseph Cudjoe Attachie Electrical and Electronic Engineering Department University of Mines and Technology Tarkwa Ghana

Voltage and frequency are usually considered and assessed independently in the design and operation of electrical networks. However, these two are linked. Each and every malfunctioning electrical system has an impact on both voltage and frequency. This paper presents the opportunity for monitoring the distributed electrical energy by means of a system that monitors, controls, and provides a breakpoint based on high or low voltage and frequency tripping mechanism that avoids any damage to the load. The designed system comprised a switch mode power supply (SMPS), a direct digital synthesizer (DDS), and PIC16F876A microcontroller techniques for stable voltage and frequency outputs. Proteus design suite version 8.11 software and Benchcope SDS1102CN were used for modeling and simulation. The hardware prototype was implemented at a telecom cell site for data capturing and analysis. Test results showed that the implementation of the prototype provided stable and constant outputs of 222 V/50 Hz and 112 V/60 Hz which constituted 99% and 99.8% efficiency for voltage and frequency performance respectively. The paper also discusses different technologies that can be adopted by the system to mitigate voltage and frequency effects on customer appliances.

关键词： Switch Mode Power Supply Direct Digital Synthesis Pulse Width Modulation H-Bridge Mosfet Microcontroller Filtering and Rectification

Estimation of Stochastic Volatility with a Compensated Poisson Jump Using Quadratic Variation

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Applied Mathematics 2017年第7期8卷 987-1000页

作者： Perpetual Saah Andam joseph Ackora-prah Sure Mataramvura Department of Mathematics Kwame Nkrumah University of Science and Technology (KNUST) Kumasi Ghana Department of Actuarial Science University of Cape Town Cape Town South Africa

The degree of variation of trading prices with respect to time is volatility-measured by the standard deviation of returns. We present the estimation of stochastic volatility from the stochastic differential equation for evenly spaced data. We indicate that, the price process is driven by a semi-martingale and the data are evenly spaced. The results of Malliavin and Mancino [1] are extended by adding a compensated poisson jump that uses a quadratic variation to calculate volatility. The volatility is computed from a daily data without assuming its functional form. Our result is well suited for financial market applications and in particular the analysis of high frequency data for the computation of volatility.

关键词： Stochastic Volatility Compensated Poisson Jump Quadratic Variation

Mathematical Morphological Distributive Concepts over Unions and Intersections

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Advances in Pure Mathematics 2016年第10期6卷 633-637页

作者： joseph Ackora-prah Robert K. Acquah Yao Elikem Ayekple Department of Mathematics Kwame Nkrumah University of Science and Technology Kumasi Ghana

Mathematical Morphological concepts outline techniques for analysing and processing geometric structures based on set theory. In this paper, we present proofs of our theorems on morphological distributive properties over Unions and Intersections with respect to Dilation and Erosion. These results provide new realizations of Dilation, Erosion and conclude that they are distributive over Unions but non-distributive over Intersections.

关键词： Mathematical Morphology Dilation Distributive

Solvability of Inverse Eigenvalue Problem for Dense Singular Symmetric Matrices

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Advances in Pure Mathematics 2013年第1期3卷 14-19页

作者： Anthony Y. Aidoo Kwasi Baah Gyamfi joseph Ackora-prah Francis T. Oduro Department of Mathematics and Computer Science Eastern Connecticut State University Willimantic USA Department of Mathematics Kwame Nkrumah University of Science and Technology Kumasi Ghana

Given a list of real numbers ∧={λ1,…, λn}, we determine the conditions under which ∧will form the spectrum of a dense n × n singular symmetric matrix. Based on a solvability lemma, an algorithm to compute the elements of the matrix is derived for a given list ∧ and dependency parameters. Explicit computations are performed for n≤5 and r≤4 to illustrate the result.

关键词： Inverse Eigenvalue Problem Dense Nonnegative Singular Symmetric

Revised Mathematical Morphological Concepts

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Advances in Pure Mathematics 2015年第4期5卷 155-161页

作者： joseph Ackora-prah Yao Elikem Ayekple Robert Kofi Acquah Perpetual Saah Andam Eric Adu Sakyi Daniel Gyamfi Department of Mathematics Kwame Nkrumah University of Science and Technology Kumasi Ghana

We revise some mathematical morphological operators such as Dilation, Erosion, Opening and Closing. We show proofs of our theorems for the above operators when the structural elements are partitioned. Our results show... 详细信息

关键词： Mathematical Morphology Dilation Erosion Opening Closing