NRU :: Browsing by Author "Ssennoga, Twaha"

Browsing by Author "Ssennoga, Twaha"

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Applying grid-connected photovoltaic system as alternative source of electricity to supplement hydro power instead of using diesel in Uganda
(Energy, 2012) Ssennoga, Twaha; Mohd, Hafizi Idris; Makbul, Anwari; Azhar, Khairuddin
Uganda’s electricity sector for long has been depending on hydro as a base power source. Diesel is currently the second source of electricity which supplements the hydro power. The use of diesel has some implications; first, the price of fuel is high and therefore the energy produced is also expensive. Secondly, diesel power would not be a better option because of its immediate and long term effect on environment due to carbon emission and other pollutants that are often injected into atmosphere from diesel. This paper therefore examines the possibility of using solar PV systems as alternative to diesel as a source of electricity. The paper has also established that the tendency of depending on nonrenewable sources of electricity can be minimized and at the same time reducing the cost of energy in the future.
Comprehensive Parameters Identification and Dynamic Model Validation of Interior-Mount Line-Start Permanent Magnet Synchronous Motors
(Machines, 2019) Maraaba, Luqman S.; Al-Hamouz, Zakariya M.; Milhem, Abdulaziz S.; Ssennoga, Twaha
The application of line-start permanent magnet synchronous motors (LSPMSMs) is rapidly spreading due to their advantages of high efficiency, high operational power factor, being self-starting, rendering them as highly needed in many applications in recent years. Although there have been standard methods for the identification of parameters of synchronous and induction machines, most of them do not apply to LSPMSMs. This paper presents a study and analysis of different parameter identification methods for interior mount LSPMSM. Experimental tests have been performed in the laboratory on a 1-hp interior mount LSPMSM. The measurements have been validated by investigating the performance of the machine under different operating conditions using a developed qd0 mathematical model and an experimental setup. The dynamic and steady-state performance analyses have been performed using the determined parameters. It is found that the experimental results are close to the mathematical model results, confirming the accuracy of the studied test methods. Therefore, the output of this study will help in selecting the proper test method for LSPMSM.
A Comprehensive Review of Thermoelectric Technology: Materials, Applications, Modelling and Performance Improvement
(Renewable and sustainable energy reviews, 2016) Ssennoga, Twaha; Yan, Yuying; Li, Bo; Zhu, Jie
Thermoelectric (TE) technology is regarded as alternative and environmentally friendly technology for harvesting and recovering heat which is directly converted into electrical energy using thermoelectric generators (TEG). Conversely, Peltier coolers and heaters are utilized to convert electrical energy into heat energy for cooling and heating purposes The main challenge lying behind the TE technology is the low efficiency of these devices mainly due to low figure of merit (ZT) of the materials used in making them as well as improper setting of the TE systems. The objective of this work is to carry out a comprehensive review of TE technology encompassing the materials, applications, modelling techniques and performance improvement. The paper has covered a wide range of topics related to TE technology subject area including the output power conditioning techniques. The review reveals some important critical aspects regarding TE device application and performance improvement. It is observed that the intensified research into TE technology has led to an outstanding increase in ZT, rendering the use TE devices in diversified application a reality. Not only does the TE material research and TE device geometrical adjustment contributed to TE device performance improvement, but also the use of advanced TE mathematical models which have facilitated appropriate segmentation TE modules using different materials and design of integrated TE devices. TE devices are observed to have booming applications in cooling, heating, electric power generation as well as hybrid applications. With the generation of electric energy using TEG, not only does the waste heat provide heat source but also other energy sources like solar, geothermal, biomass, infra-red radiation have gained increased utilization in TE based systems. However, the main challenge remains in striking the balance between the conflicting parameters; ZT and power factor, when designing and optimizing advanced TE materials. Hence more research is necessary to overcome this and other challenge so that the performance TE device can be improved further.
Contamination Level Monitoring Techniques for High-Voltage Insulators: A Review
(Energies, 2022) Maraaba, Luqman; Al-Soufi, Khaled; Ssennoga, Twaha; Memon, Azhar M.; Worku, Muhammed Y.
Insulators are considered one of the most significant parts of power systems which can affect the overall performance of high-voltage (HV) transmission lines and substations. High-voltage (HV) insulators are critical for the successful operation of HV overhead transmission lines, and a failure in any insulator due to contamination can lead to flashover voltage, which will cause a power outage. However, the electrical performance of HV insulators is highly environment sensitive. The main cause of these flashovers in the industrial, agricultural, desert, and coastal areas, is the insulator contamination caused by unfavorable climatic conditions such as dew, fog, or rain. Therefore, the purpose of this work is to review the different methods adopted to identify the contamination level on high-voltage insulators. Several methods have been developed to observe and measure the contamination level on HV insulators, such as leakage current, partial disgorgement, and images with the help of different techniques. Various techniques have been discussed alongside their advantages and disadvantages on the basis of the published research work in the last decade. The major highvoltage insulator contamination level classification techniques discussed include machine learning, fuzzy logic, neuro–fuzzy interface, detrended fluctuation analysis (DFA), and other methods. The contamination level data will aid the scheduling of the extensive and costly substation insulator, and live line washing performed using high-pressured water. As a result, considerable benefits in terms of improved power system reliability and maintenance cost savings will be realized. This paper provides an overview of the different signal processing and machine-learning methods adopted to identify the contamination level on high-voltage insulators. Various methods are studied, and the advantages and disadvantages of each method are discussed. The comprehensive review of the islanding methods will provide power utilities and researchers with a reference and guideline to select the best method to be used for contamination level identification based on their effectiveness and economic feasibility.
Economic analysis of PV/diesel hybrid system with flywheel energy storage
(Renewable Energy, 2015) Ramli, Makbul A.M.; Ayong, Hiendro; Ssennoga, Twaha
This paper analyzes a hybrid energy system performance with photovoltaic (PV) and diesel systems as the energy sources. The hybrid energy system is equipped with flywheel to store excess energy from the PV. HOMER software was employed to study the economic and environmental benefits of the system with flywheels energy storage for Makkah, Saudi Arabia. The analysis focused on the impact of utilizing flywheel on power generation, energy cost, and net present cost for certain configurations of hybrid system. Analyses on fuel consumption and carbon emission reductions for the system configurations were also presented in this paper.
Energy production potential and economic viability of gridconnected wind/PV systems at Saudi Arabian coastal areas
(Journal of Renewable and Sustainable Energy, 2017) Makbul A. M., Ramli; Ssennoga, Twaha; Abdulaziz U., Alghamdi
This paper analyzes the electricity production potential and economic viability of grid-connected wind/photovoltaic (PV) energy systems at two coastal cities, Yanbu and Dhahran in Saudi Arabia. First, wind energy is assessed based on the hourly wind speed observation data recorded over the entire year 2013 in the selected locations. Electricity generation potential is estimated using two wind turbines: Vestas V82 and V90 models. The results indicate that both locations have sufficient wind resources for wind turbine operation. Strong wind resources are more common at Dhahran than at Yanbu with wind speeds above 3.5m/s, accounting for 60.12% of the wind data at Dhahran, which is higher than 51.2% of Yanbu. Grid-connected hybrid systems using Vestas V90 wind turbines had the highest net present cost (NPC) compared with other configurations. The inclusion of battery storage units slightly increases the NPC. Surprisingly, systems with the highest NPC produced the least electricity. In contrast, cheaper V82-based systems had the lowest NPC and levelized cost of energy and produced the most electricity. Hence, a grid-connected wind/PV system using V82 turbines is most economically viable. Incorporating a small battery storage unit in the systems minimizes capacity shortages and improves reliability at minimal extra cost. Using different wind turbines with a lower cut-in speed of 3 m/s could increase the electricity production, as 9.1% and 10.3% of wind observations at Yanbu and Dhahran, respectively, had a wind speed of 3m/s.
Heat Transfer Enhancement of a Modularised Thermoelectric Power Generator for Passenger Vehicles
(Applied Energy, 2017) Li, Bo; Kuo, Huang; Yuying, Yan; Yong, Li; Ssennoga, Twaha; Jie, Zhu
Transport represents over a quarter of Europe's greenhouse gas emissions and is the leading cause of air pollution in cities. It has not seen the same gradual decline in emissions as other sectors. Recently, the thermoelectric power generation (TEG) technology emerges as an alternative solution to the emission reduction challenge in this area. In this paper, we present an innovative pathway to an improved heat supply into the concentric shape-adapted TEG modules, integrating the heat pipe technologies. It relies on a phase changing approach which enhances the heat flux through the TEG surface. In order to improve the heat transfer for higher efficiency, in our work, the heat pipes are configured in the radial direction of the exhaust streams. The analysis shows that the power output is adequate for the limited space under the chassis of the passenger car. Much effort can also be applied to obtain enhanced convective heat transfer by adjusting the heat pipes at the dual sides of the concentric TEG modules. Heat enhancement at the hot side of the TEG has an effective impact on the total power out of the TEG modules. However, such improvements can be offset by the adjustment made from the coolant side. Predictably, the whole temperature profile of TEG system is subject to the durability and operational limitations of each component. Furthermore, the results highlight the importance of heat transfer versus the TEG power generation under two possible configurations in the passenger car. The highest power output per repeat unit is achieved at 29.8 W per 0.45 Litre with a ZT value 0.87 for a Bi2Te3-based thermoelectric material in our studies. The study provides an insight into a structurally achievable heat exchanger system for other high-temperature thermoelectric materials.
Maximum Power Point Tracking Control of a Thermoelectric Generation System Using the Extremum Seeking Control Method
(Energies, 2017) Ssennoga, Twaha; Zhu, Jie; Maraaba, Luqman; Huang, Kuo; Li, Bo; Yan, Yuying
This study proposes and implements maximum power Point Tracking (MPPT) control on thermoelectric generation system using an extremum seeking control (ESC) algorithm. The MPPT is applied to guarantee maximum power extraction from the TEG system. The work has been carried out through modelling of thermoelectric generator/dc-dc converter system using Matlab/Simulink. The effectiveness of ESC technique has been assessed by comparing the results with those of the Perturb and Observe (P&O) MPPT method under the same operating conditions. Results indicate that ESC MPPT method extracts more power than the P&O technique, where the output power of ESC technique is higher than that of P&O by 0.47 W or 6.1% at a hot side temperature of 200 C. It is also noted that the ESC MPPT based model is almost fourfold faster than the P&O method. This is attributed to smaller MPPT circuit of ESC compared to that of P&O, hence we conclude that the ESC MPPT method outperforms the P&O technique.
Optimal sizing of grid-connected photovoltaic energy system in Saudi Arabia
(Renewable Energy, 2015) Makbul, A.M. Ramli; Ayong, Hiendro; Khaled, Sedraoui; Ssennoga, Twaha
Resource optimization is a major factor in the assessment of the effectiveness of renewable energy systems. Various methods have been utilized by different researchers in planning and sizing the gridconnected PV systems. This paper analyzes the optimal photovoltaic (PV) array and inverter sizes for a grid-connected PV system. Unmet load, excess electricity, fraction of renewable electricity, net present cost (NPC) and carbon dioxide (CO2) emissions percentage are considered in order to obtain optimal sizing of the grid-connected PV system. An optimum result, with unmet load and excess electricity of 0%, for serving electricity in Makkah, Saudi Arabia is achieved with the PV inverter size ratio of R ¼ 1 with minimized CO2 emissions. However, inverter size can be downsized to 68% of the PV nominal power to reduce the inverter cost, and hence decrease the total NPC of the system.
Parameter Analysis of Thermoelectric Generator/dc-dc Converter System with Maximum Power Point Tracking
(Energy for Sustainable Development, 2017) Ssennoga, Twaha; Zhu, Jie; Li, Bo; Yan, Yuying; Huang, Kuo
The power generated from TEG is relatively unstable owing to temperature variations at its hot and cold side terminals. The dc-dc converters can provide more stable power output thereby improving the overall efficiency of TEG system. However, to facilitate better performance improvement, maximum power point tracking (MPPT) algorithm can be applied to extract maximum power from TEG system. Therefore, parameter analysis of a TEG/dc-dc converter system in different modes is being carried out. A TEG-dc-dc boost converter model is analysed in both MPPT and direct pulse width modulation (PWM) modes subjected to a variable load. To further study the capability of dc-dc converters to stabilise the TEG power output, increasing ramp and random hot side temperature is applied to the MPPT and direct PWM based modes so that the effect on output parameters i.e. voltage and power, can be analysed. It is noted that even for the random temperature input to the TEG, the output voltage resulting from the converter is almost constant. Therefore dc-dc converters are able to stabilise the power generated from TEG. It is also observed that dc-dc converter with MPPT based model is able to effectively extract the maximum power without having to adjust any component from the MPPT algorithm as it is the case with direct PWM based model. From the study, it has been established that proper selection of converter components is necessary to reduce converter losses as well interferences on the load connected to TEG-dc-dc converter system.
Performance analysis of thermoelectric generator using dc-dc converter with incremental conductance based maximum power point tracking
(Energy for Sustainable Development, 2017) Ssennoga, Twaha; Jie, Zhu; Yuying, Yan; Bo, Li; Kuo, Huang
Thermoelectric (TE) devices are regarded as alternative and environmentally friendly for harvesting and recovering heat energy. Particularly, thermoelectric generators (TEGs) are used for converting heat into electricity. One of the challenges behind TEG is that the power generated is unstable and therefore needs proper power conditioning mechanism before it is supplied to the load. Moreover, it is necessary to track the maximum power point (MPP) at all times so that maximum power is always extracted from TEG devices. The objective of this work is to analyse the performance of a dc-dc converter with maximum power point tracking (MPPT) enabled by incremental conductance (IC) method. The simplified model is used as the basis for TEG design while the dc-dc boost converter is used for boosting and stabilising the power generated from TEG. The results of the IC based MPPT approach have been compared with those of perturb and observe (P&O) based MPPT from a previous researcher. The results indicate that the IC based MPPT approach is able to track the MPP but with relatively lower efficiencies than the P&O based MPPT method. The matching efficiency within a temperature range of 200oC– 300oC is in the range of 99.92% - 99.95% for P&O and 99.46% - 99.97% for IC method. However IC based MPPT method has higher voltage gain and converter efficiency than the P&O based MPPT method. Therefore, dc-dc converters are able to improve the steady state performance of TEG system as well as boosting the voltage to the desired level, hence improving the overall performance of TEG system. Although both P&O and IC are two classical algorithms that can be implemented to extract the maximum power from TEG, the comparative study has established that P&O technique outperforms the IC method.
Performance Comparison of SVM and ANN in Predicting Compressive Strength of Concrete
(IOSR Journal of Computer Engineering, 2014) Kabiru, O. Akande; Owolabi, Taoreed O.; Ssennoga, Twaha; Olatunji, Sunday O.
Concrete compressive strength prediction is very important in structure and building design, particularly in specifying the quality and measuring performance of concrete as well as determination of its mix proportion. The conventional method of determining the strength of concrete is complicated and time consuming hence artificial neural network (ANN) is widely proposed in lieu of this method. However, ANN is an unstable predictor due to the presence of local minima in its optimization objective. Hence, in this paper we have studied the performance of support vector machine (SVM), a stable and robust learning algorithm, in concrete strength prediction and compare the result to that of ANN. It is found that SVM displayed a slightly better performance compared to ANN and is highly stable.
Plagiarism Detection Scheme Based on Semantic Role Labeling
(IEEE, 2012) Hamza Osman, Ahmed; Salim, Naomie; Salem Binwahlan, Mohammed; Jaya Kumar, Yogan; Abuobieda, Albaraa; Ssennoga, Twaha
Nowadays, many documents are available on the internet and are easy to access. Due to this wide availability, users can easily create a new document by copying and pasting. Plagiarism occurs when the content is copied without permission or citation. This paper introduces a plagiarism detection technique based on the Semantic Role Labeling (SRL). The technique analyses and compares text based on the semantic allocation for each term inside the sentence. SRL is superior in generating arguments for each sentence semantically. In addition, experimental results on PAN-PC-09 data sets showed that our method outperforms the modern methods for plagiarism detection in terms of Recall, Precision and F-measure.
Recognition of Stator Winding Inter-Turn Fault in Interior-Mount LSPMSM Using Acoustic Signals
(Symmetry, 2020) Maraaba, Luqman S.; Ssennoga, Twaha; Memon, Azhar; Al-Hamouz, Zakariya
This paper presents a novel stator inter-turn fault diagnosis method for Line Start Permanent Magnet Synchronous Motors (LSPMSMs) using the frequency analysis of acoustic signals resulting from asymmetrical faults. In this method, acoustic data are experimentally collected from a 1 hp interior mount LSPMSM for di erent inter-turn fault cases and motor loading levels, while including the background noise. The signals are collected using a smartphone at a sampling rate of 48,000 samples per second. The signal for each case is analyzed using fast Fourier transform (FFT), which results in the decomposition of the signal into its frequency components. The results indicate that, for both no-load and full-load conditions, 39 components are observed to be a ected by the faults, whereby their amplitudes increase with the fault severity. The 40-turns fault shows the highest di erence in the component amplitudes compared with the healthy condition acoustic signal. Therefore, this diagnostic method is able to detect the stator inter-turn fault for interior mount LSPMSMs. Moreover, the method is simple and cheap since it uses a readily available sensor
Renewable based distributed generation in Uganda: Resource potential and status of exploitation
(Renewable and Sustainable Energy Reviews, 2016) Ssennoga, Twaha; MakbulA.M., Ramli; Patrick M., Murphy; Muhammad U., Mukhtiar; Nsamba, Hussein K.
Uganda is gifted by nature with abundant energy resources, mainly renewables, which can potentially provide the country with sufficient capacity to meet future growth in energy demand. Surprisingly, Uganda has one of the lowest electricity penetration levels, with only 9–12% of the total population having electricity access;2–3% of them living in rural communities. There is multitude of challenges facing the energy sector of Uganda, forcing energy demand to always exceed the supply. For decades, hydro power has been and is still the base electricity supply of the country with a supplement of limited biomass, diesel based thermal and solar electricity. The objective of this paper is to review the potential and progress of renewable based distributed generation in Uganda. The potential of the country’s natural renewable resources and existing distributed generation is described and existing government policies are assessed.The challenges facing the energy sector and the suggested remedies are discussed.Various distributed generation systems that could be incorporated into the energy system of the country to improve renewable energy(RE) utilization and possibly contribute to the electricity needs of the population are also proposed and discussed. Exploitation of abundant RE resources through distributed energy generation around the region will not only improve the electricity needs of the country but also increase the economic welfare of the growing population.
Techno-economic assessment of the horizontal geothermal heat pump systems: A comprehensive review
(Energy Conversion and Management, 2019) Cui, Yuanlong; Zhu, Jie; Ssennoga, Twaha; Chu, Junze; Bai, Hongyu; Huang, Kuo; Chen, Xiangjie; Zoras, Stamatis; Soleimani, Zohreh
Geothermal heat pump has been widely recognized as one of the promising technologies for building applications because of its high energy efficiency and low operating expense, however the high capital investment and installation costs discourage building owners to choose such a system. The horizontal geothermal heat pump system with reduced cost is a viable option that would be utilized widely, the aim of this paper is to catalogue and critique a range of effective approaches for the horizontal geothermal heat pump systems in different regions based on techno-economic assessment data. A ground heat exchanger is a vital component of the horizontal geothermal heat pump. The state-of-the-art analytical and numerical models of the linear-loop, slinky-coil and spiral-coil ground heat exchangers are generalized, in addition to their advantages and disadvantages. A large number of economic evaluation methods for analysing the financial performance of the horizontal geothermal heat pump system are presented. At the end, the standpoints, recommendations and potential future study on the horizontal geothermal heat pump system are deliberated.

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