Electrical Engineering-Scholarly Publications

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Browsing Electrical Engineering-Scholarly Publications by Author "Akinbulire, T.O."

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    Open Access
    ANALYSIS OF THE TRANSIENT STABILITY LIMIT OF NIGERIA’S 330kV TRANSMISSION SUB-NETWORK
    (Faculty of Engineering, University of Nigeria, Nsukka, 2017-01) Oluseyi, P.O.; Adelaja, T.S.; Akinbulire, T.O.
    The poor investment in the network expansion programme has led to high level of grid fragility experienced in the power transmission system in Nigeria. Thus, any little disturbance often results in cascaded outage which is very hazardous to the power system equipment and operation. In order to overcome or ameliorate the influence of this challenge, the network engineers have to devise methodologies based on the dynamic stability analysis. This motivates the development of power system transient stability model presented herein. The developed model is thus applied to a specimen of the Nigeria’s transmission power system, i.e. the Ikeja-West Sub-network. This choice is influenced by the fact that the Ikeja-West sub-network is the hub of power transmission arteries in Nigeria. Thus the Electrical Transient and Analysis Program (ETAP) software is deployed to operate on the ensuing model. This then leads to generating a series of results that demonstrates the different scenarios in respect of the system stability studies. The method adopted is quite appealing and promising as a tool in sustaining system stability and security during slight disturbance to the network during operation.
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    Open Access
    Assessment of electrical grid fragility in Nigeria-31 bus system
    (Faculty of Engineering, University of Maiduguri, Maiduguri, Nigeria., 2018-12) Oluseyi, P.O.; Ajekigbe, T.O.; Babatunde, O.M.; Akinbulire, T.O.
    The grid fragility is a prevalent challenge in Nigeria electricity supply industry (NESI). It has resulted in recorded incidents of voltage collapse which have been on the increase in the recent time. Meanwhile to evaluate this events; thus the nexus between voltage collapse and network capacity was explored. To actualize this, the load flow analysis was carried out on the Nigeria-31 bus system with the aid of the Newton-Raphson iteration technique. Using the relevant parameters (such as bus voltage magnitude, bus voltage angle, generated power, injected power as well as load magnitude) obtained from the analysis, the line stability index and line stability factor were obtained for every line in the network. It was discovered from the values of line stability index that Lines (26-2); (31-7); (10-11); (24-10) and (18-12) are weak and fragile while for the line stability factor, the values obtained for Lines (10-8); (11-8); (11-10); (24-10) and (18-12) indicate the fragility of some of the lines in the Nigerian Transmission Network. From this, it was established that the weakest lines were those whose values range from 0.3051 to 0.8813 for the line stability index. Correspondingly; any line that takes the value between 0.2737 and 0.9924 in respect of the line stability factor was also marked as the weakest lines in the network. Thus it was noticed that for the two line stability indices (i.e. stability factor and stability index); Line (11-10) i.e. from Oshogbo to Ikeja- West bus is the most fragile line in Nigeria-31 bus transmission network while the nearest to it are lines (24-10) i.e. from Ayede to Ikeja-West bus and (12-18) i.e. from Kaduna to Kano bus. This study is potentially sufficient for determining the lines in the transmission network that require utmost consideration for reinforcement in respect of the transmission expansion planning schemes.
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    Open Access
    Comparative Load Flow Analysis of UNILAG Power Distribution Network using Newton Raphson and Gauss Seidel Methods
    (Faculty of Engineering, University of Benin, Benin City, Nigeria, 2019-06) Akinbulire, T.O.; Oluseyi, P.O.; Udoakam, G.A.; Babatunde, O.M.
    The evaluation of power flow in the distribution network has many techniques but there has been a very much interest in the traditionally known methods. These methods have enjoyed very wide acceptability and applicability. However, a comparative study of these techniques for the investigation of the load flow analysis for any of the Nigeria’s distribution systems is not adequately and proficiently documented. Thus, this inspired the adaptation of these techniques for the solution of a structured distribution network in the University of Lagos (UNILAG) Campus. The opportunity presented by this research is the deployment of these methods for the analysis and testing of a reallife power distribution network. The results obtained were validated with the IEEE-9 bus and IEEE-30 bus systems. The results obtained for the Campus distribution network were not only highly revealing but it also provided comparatively information (in respect of GS versus NR) as follows: number of iterations (i.e. 3 versus 177) , convergence time (i.e. 0.2457 versus 0.3276), power mismatch (0.017 MVAr versus 0.00 MVAr), system losses (i.e. 0.854 MW versus 0.855 MW), iteration tolerance (0.00001 versus 0.00) From this, the compared results indicated that the NR method converges faster with a least number of iterations irrespective of the number of the system buses while in the GS method, the number of iterations increases proportionally as the number of buses increases. Thus, it is evidently established that the NR method is very adequate for the analysis of large distribution networks.
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    Open Access
    Development of a model for mitigating fire spread in multi-storey buildings
    (Faculty of Engineering University of Maiduguri, Maiduguri- Nigeria, 2019-06) Oluseyi, P.O.; Akinbulire, T.O.; Atunbi, C.T.; Akinyemi, M.I.
    In the developing nations that are located in the tropical region; there is a growing trend of fire incidence in buildings without adequate development of fire prevention and/or reduction protocol. Thus, this study addresses the growth and spread of fire in multi-storey buildings. The rooms are structured as cells in order to reduce the flame spread from a single fuel item, by heat release, to other neighbouring items or rooms (otherwise known as cells). The philosophy is to reduce the advent of vertical and horizontal fire spread. Thus, the mathematical model for the spread of fire in buildings over a solid fuel surface is therefore developed using the adaptation, development and simulation of cellular automata (CA) discrete model. The von Neumann neighbourhood cell configuration is adopted. Hence, the surface of the fuel is analysed using a regular square array (i.e. cells), while the flame spread is depicted as a series of ignitions of surface elements. In which case, ignition of an element is evaluated by a combination of critical surface ignition temperature and cellular automata discrete techniques. The work displays the movement of fire, from its origin of ignition to other fuel igniting elements around it. Consequently, this spread to other parts of the building. However, the technique presented in this work attempts to reduce the rate of growth of the fire spread using the predictive fire growth probability approach. In other words, the application of the cellular automata, using a multi-storey building, is herein presented. The study has potential to advance knowledge of technical approach to stop fire spread in multi-storey building. Thus it improves fire risk management as well as reducing magnitude of fire disaster and losses in the multi-storey buildings.
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    Open Access
    Development of energy benchmarking protocol for commercial banks, Lagos state, Nigeria
    (Routledge Taylor & Francis, 201-09-26) Akinbulire, T.O.; Oluseyi, P.O.; Babatunde, O.M.; Ayegbajeje, A.E.
    Energy consumption is a central factor taken into consideration as far as management decisions are concerned in any firm and the same goes for the banking industry. More importantly is the extent to which firms consume energy efficiently. In the light of this, this study investigates the energy benchmarking of 50 commercial bank branches in Lagos. With the aid of questionnaires and by observation and consultation with the staff of the selected bank branches, data were collected on the energy use as well as several other variables that influence energy use intensity. An energy use intensity model was estimated using the fixed, random and pooled ordinary least square specifications and the predicted energy use intensity was constructed. Armed with the observed and predicted energy use intensities, an absolute benchmarking was conducted while a relative benchmarking was also conducted with the aid of the Data Envelopment Analysis (DEA) technique. The results of the regression analysis revealed a maximum of 60% of the branches of banks are energy efficient. However, the results of the DEA suggest that only a single branch of the 50 sampled branches was energy efficient while the other banks fell below the energy efficiency frontier with some banks performing relatively poorer than the others.
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    Open Access
    Evaluating the Energy and Carbon (IV) Oxide (CO2) Reduction Resulting from Efficient Lighting at the University of Lagos, Nigeria
    (Faculty of Engineering, University of Lagos, Nigeria, 2017-12) Babatunde, O.M.; Akinbulire, T.O.; Oluseyi, P.O.; Emezirinwune, M.U.; Shomefun, T.E.
    This study evaluated the economic and environmental potentials of improving the energy efficiency of the lighting technology at the University of Lagos, Nigeria. The energy audit report for the Faculty of Engineering, University of Lagos before retrofitting shows that all lighting fixtures in the lecture rooms are the 1.2 metre inefficient fluorescent lamps. The cost effectiveness of lighting retrofitting with Compact Fluorescent Lamps (CFL) and Light Emitting Diode tube (LED) lighting technology alternatives for the lighting system at Faculty of Engineering lecture rooms were analysed using economic indices such as life cycle cost analysis, net present cost, simple payback time, and internal rate of return. Relative to the existing system, installation of the two lighting technology alternatives would result in a 40 % and 72 % reduction of consumed energy respectively. With both technology alternatives paying back in less than two years, the LED technology returned a NPV of $35,791.76 (N12.95M) compared to the $15,261.43 (N5.24M) given back by the CLF lighting fixtures. If the alternative lighting technology that conserves the most electricity was installed, carbon dioxide emissions accompanying electricity usage would be reduced by about 72 % and a savings of 3.84 tonnes of oil would be achieved annually. From the study, it was established that the utilisation of energy efficient lighting system will reduce energy consumption; increase bills savings; and indirectly reduce carbon (IV) oxide emission from the fossil fuel used in powering the lamps
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    Open Access
    Evaluation of a grid-independent solar photovoltaic system for primary health centres (PHCs) in developing countries
    (Elsevier/Science Direct, 2018-03) Babatunde, O.M.; Akinyele, Daniel; Oluseyi, P.O.; Akinbulire, T.O.
    This paper presents the evaluation of a stand-alone solar photovoltaic (PV) electricity supply system for rural primary health centres (PHCs) in developing countries, using a PHC at Abadam local government area in North-West Nigeria as a case study. The paper is guided by standards for sizing and estimating the performance of stand-alone PV/battery systems. The research presents PV/battery/inverter capacity, yield and losses, battery state of charge, reliability and load growth analysis. The economic analysis is based on the life cycle cost assessment approach, while the environmental evaluation is considered in terms of the quantity of diesel fuel and carbon emissions avoided by the proposed solar PV system. A PV system capacity of 3.6–6 kW is designed for the clinic’s total daily demand plus 25% load growth, with a yield of 4.6 h/d. This energy system can achieve a high availability over the year. The initial, life cycle, O and M and the replacement costs range from $ 14,356 to $ 14,506, $ 17,909 to $ 18, 080, $ 1534 and $ 4451 to $ 4498, while the cost of energy ranges from $ 0.239 to $ 0.295/kWh. The diesel system which has an initial cost of $ 451 has a relatively higher life cycle cost of $ 38,135–$ 40,460. The proposed PV system has the potential to avoid 8357–8956 kg/year of CO2 after implementation.
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    Open Access
    Hybrid Energy Systems Model with the Inclusion of Energy Efficiency Measures: A Rural Application Perspective
    (Econ Journal, 2018) Babatunde, D.E.; Babatunde, O.M.; Akinbulire, T.O.; Oluseyi, P.O.
    The wide energy supply/demand gap has led the developing economies to the operation of the captive generators. This has contributed in no small way to the carbon footprint in the developing nations. Thus, the energy management initiative could assist in reducing the menace of greenhouse gas emission. Hence, the energy policy makers and planners have unanimously proposed adoption of demand side management (DSM) technique. Thus the adoption of energy efficiency technique (EET)-a DSM measures and hybrid energy system would be essential for rural electrification. This work investigates the effect of applying energy efficiency measures in rural electrification. Acase study of an un-electrified rural settlement in Ibadan, Nigeria was considered. The utilization of EET techniques reduces the emission of CO2 by 62%, while the technical analysis indicates the possibility of a 100% renewable electricity production. Principally, the adoption of energy efficient techniques proved to be economically and environmentally friendly.
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    Open Access
    INVESTIGATION OF THE LIGHTNING ARRESTER OPERATION IN ELECTRIC POWER DISTRIBUTION NETWORK
    (Faculty of Engineering, University of Nigeria, Nsukka, 2018-04) Oluseyi, P.O.; Akinbulire, T.O.; Amahian, O.
    Lightning phenomenon has resulted into several losses to both supply-side and load-side of the electricity infrastructure. Quite a handful of research has investigated strategies for its mitigation. This work is an application of the Fernandez-Diaz arrester model to the section of Eko Distribution network. The procedure involves simulation of the network in respect of the influence of the surges and surge arresters using MATLAB/SIMULINK. The study reveals that whenever lightning strikes, the resulting overvoltage causes distortion to the voltage waveform, as well as the current waveform. This indicates the presence of harmonics. Meanwhile, with the installation of the arresters, the overvoltage reduces by 86% at the nearest node of installation. However, at the other nodes within the same branch, the installed arrester attenuated the surge overvoltage by approximately 60%. This suggests that more arresters need to be installed at other nodes along the branch in order to eliminate the occurrence of overvoltage. Moreover, the study reveals that a surge arrester installed at one of the two branches of the network has negligible effect in attenuating voltage surge at the other branch of the same network.
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    Open Access
    Long-Term Electric Load Forecasting for University of Lagos Using Regression Analysis Method
    (Faculty of Engineering, University of Lagos, Nigeria, 2010-03) Akinbulire, T.O.; Oluseyi, P.O.; Awosope, C.O.A.; Odekunle, M.; Idowu, O.M.
    The university as a centre for research into the development of a nation requires constant supply of electricity. In order to achieve this, it becomes of great importance to evaluate the precise amount of energy required for continuous and uninterrupted power supply to the academic community. In line with this goal, this work investigates the historical load consumption of the University of Lagos community from which an electrical load forecast for the future energy requirement for this community can be proffered using the regression analysis method. It is the intent of this work to establish a mathematical model via the regression analysis method for the assessment of the historical data in order to predict a fairly reliable future energy requirement for the community; with special consideration for the next one decade, i.e. long-term forecasting. Even though this method is examined using the University community, it can be further extended to cover the whole country, provided the historical data of the country’s past electric energy consumption are available.
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    Open Access
    Optimal load frequency control of two area power system
    (Faculty of Engineering, Ahmadu Bello University, Samaru-Zaria, Nigeria, 2019-08) Oluseyi, P.O.; Akinbulire, T.O.; Yellowe, K.M.; Babatunde, O.M.; Alayande, A.S.
    Modern power systems are operated under various constraints which are meant to ensure an appropriate delivery of service. Meanwhile power system faces imbalance in power generation and its consumption in which the higher the load consumption the lower the frequency of operation. The governor-turbine combination will then experience a devastating reduction in its frequency of operation due to disturbance that may lead to system collapse. Both governor and turbine are included in the model of this power system. The control objective is to regulate the frequency error, tie-line power error and area control error despite the presences of external load disturbance (0.01 pu) and system uncertainties. Various control policies were investigated using various combinations of system parameters on a platform of a series of combination of the PI, fuzzy logic and neuro-fuzzy controller with the power system for better stability. This could be found in the other approaches. The neuro-fuzzy based controller load frequency controller is simulated on this two-area interconnected nonlinear power system. To verify the performance of the various controllers, the data from a typical hydrothermal power grid was adapted for the study. From the simulation results; it was recorded the neuro-fuzzy controller enjoyed a settling time of 5 seconds while under the same operating condition the system stability is achieved at 12 seconds using the PI controller. This, thus, demonstrates the robustness of the neuro-fuzzy controller in contrast to the fuzzy logic and proportional-integral (PI) controllers. This thus shows that the neuro-fuzzy logic controller is superior to the other two considered in this work. Hence for a two-area network, the neuro fuzzy approach is recommended for the steady state operation of the system so as to ensure the dynamic stability of the network.
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    Open Access
    Recurrent Neural Network Model for Forecasting Electricity Demand in Nigeria
    (Journal of Engineering Research, 2016-12) Abdulsalam, K.A.; Adegbenro, O; Akinbulire, T.O.
    This work uses modular recurrent neural network to estimate the electricity demand in Nigeria from 2015 to 2050. The network is a 2-layer multi-input, single-output model with twelve neurons trained using Levenberg-Marquardt algorithm. The data structure used for training is cell array of sequential concurrent data. The Recurrent Neural Network model was simulated as Non-linear Auto Regressive with eXogenous (NARX) model in Matlab environment and the predicted load for 2015 is about 550GWh; and an expected demand increase of 7.5 % every five year.
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    Open Access
    The Role of Demand-Side Management in Carbon Footprint Reduction in Modern Energy Services for Rural Health Clinic
    (Elsevier/ Butterworth-Heinemann, 2018) Babatunde, O.M.; Oluseyi, P.O.; Akinbulire, T.O.; Denwigwe, H.I.; Akin-Adeniyi, T.J.
    Because of globalization, industrialization, and development due to technology, the demand for electrical energy is on the increase. There is therefore a need for efficient energy measures to ensure conservation, thereby saving costs. Demand-side management (DSM) deals with conversion of energy demand of consumers into activities/programs/tactics (e.g. financial incentives and public awareness/education), which brings about less use of energy by the consumers. Gellings and Parmenter gave a history of DSM in the United States and its influence on energy resources. They also explained the role of DSM in integrated resource planning, the main elements of DSM programs and summarized the key best practices for program design and delivery. Palensky and Dietrich (2011) described DSM as using measures such as sophisticated real-time control of distributed energy resources, better materials, smart energy tariffs with incentives for certain consumption patterns to improve energy efficiency. Various types of DSM were analyzed, and an overview of modern DSM projects was given. Haney et al. (2010) highlighted how integrated government DSM policies, targeting residential demand for electricity and heat are more likely.
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    Open Access
    A study of the effects of electricity supply regulation on Nigerian consumers
    (Faculty of Engineering, University of Lagos, Nigeria, 2010-06) Akinbulire, T.O.; Oluseyi, P.O.; Awosope, C.O.A.; Okafor, R.C.
    The work examines the need for the establishment of independent regulatory activities in Nigeria to make the process of price regulation more efficient, consistent and predictable and amenable to arbitrary judgement of regulators. It also examines the need for private sector participation and reforms in the energy sector so that such can secure the supply of electricity.
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    Open Access
    Techno-economic viability of off-grid standalone PV-powered LED street lighting system in Lagos, Nigeria
    (Routledge Taylor & Francis, 2019-04-23) Babatunde, O.M.; Akinbulire, T.O.; Oluseyi, P.O.; Emezirinwune, M.U.
    The majority of the street lighting systems in Nigeria are predominantly composed of inefficient lighting fixtures powered either by the grid or diesel generators. Due to the epileptic nature of the grid and the fluctuations in diesel fuel pump prices, these methods for powering street lights are neither reliable nor sustainable. Use of energy-efficient lamps and photovoltaic (PV) panels has the tendency to reduce energy consumption and emissions. This study therefore presents a techno-economic analysis of deploying energy-efficient PV-powered street lighting systems using simple economic metrics. Environmental benefits of the proposed systems were also assessed by analyzing the reduction in CO2 emission as well as the equivalent of oil saved. Relative to the existing grid-powered metal halide system, installation of LED PV-powered street light reduced energy consumption by at least 80%, while the grid-powered LED configuration reduced energy consumption by 80%. Economic analysis shows that the simple payback period (SPP) for the LED PV-powered technology was less than three years, while that of the grid-powered LED system was less than two years. The LED PV-powered technology had the highest CO2 emission reduction of approximately 225 tonnes annually. Overall, street lighting using PV-powered and grid-powered LED is economically viable considering the payback time, net present value (NPV) and lifetime.