Titus AJEWOLE - Profile on Academia.edu (original) (raw)

Papers by Titus AJEWOLE

Uniosun Journal of Engineering and Environmental Services, Mar 20, 2024

This paper presents the comparative studies among the predictive models used for the validation o... more This paper presents the comparative studies among the predictive models used for the validation of the key parameter indicators of mobile network operators with the Nigerian Communication Commission's threshold. Four Key Performance Indicators were predicted using artificial neural networks and ensemble models which include bagging and LSBoost models. The Key Performance Indicators and weather parameters for six locations in Southwestern Nigeria were employed. MATLAB R2020a was employed to develop the three models. Microsoft Excel was used in the analysis of the dataset. The bagging model gave the best average compliance of 94% and 100% for CSSR and TCH Congestion Rate respectively while the ANN model yielded the best average compliance of 76.7% and 85.2% for DCR and SDCCH Congestion Rate respectively.

Tanzania Journal of Engineering and Technology/Tanzania Journal of Engeering and Technology, Nov 7, 2023

This work proposes deployment of machine learning in the maintenance of individual constituent pa... more This work proposes deployment of machine learning in the maintenance of individual constituent parts of steam power plant assemblages. With the condenser vacuum of a steam turbine (in a six-turbine plant assemblage) taken as a case study, information on the past operating parameters of the selected plant component was used to forecast its future working condition. Based on Exponential Gaussian Process of Regression, a model was developed, trained using the diachronic operational data, and employed in determining the future. A quantitative evaluation was employed to provide the distribution of the test values of the data about the lines of regression, as well as to measure the prediction accuracy of the model. The results show MAE and RMSE values are 6.1602 and 7.9286 respectively during the training; while for the prediction, the values are 92.6544 and 92.7235 respectively. It is concluded that modern power plants with myriads of instrumentation and data acquisition mechanisms can leverage on the approach of this study to model and plan the maintenance scheme that best suits and fits individual component units of power plants, since understanding of the anticipatory values of operational parameters helps to determine the likelihood of components failures.

Journal of digital food, energy & water systems, Dec 30, 2023

This paper investigates the effect of Support Vector Regression hyperparameters optimization on e... more This paper investigates the effect of Support Vector Regression hyperparameters optimization on electrical load prediction. Accurate and robust load prediction helps policy makers in the energy sector to make inform decision and reduce losses. To achieve this, Bayesian optimization technique was employed for the hyperparameters optimization which are then used for the load prediction. The hyperparameters are the regularization parameters and the epsilon. In addition, the effects of sliding window during the load prediction were also evaluated. The sliding window values were varied from 1 to 5. The results showed that the sliding window of 1 had the optimized hyperparameters with the best performing evaluation metrics of 0.01912 and 0.09493 for MSE and MAE respectively.

Agro-residues for clean electricity: in-lab trial of power generation from blended cocoa-kolanut wastes

Heliyon, Mar 1, 2022

As a way of wastes-to-voltage conversion, experimental benchtest trial of electricity generation ... more As a way of wastes-to-voltage conversion, experimental benchtest trial of electricity generation from a blend of cocoa and kolanut harvest by-products is presented in this study. Bioethanol obtained from the blend, through a process of alcoholic fermentation, was mixed with gasoline at specific proportion and employed to fire a spark ignition engine that served as a prime-mover in driving a four-pole three-phase salient-pole synchronous machine. Performance of the driving machine, as the fuel-mix proportion and its speed of rotation varied, was studied. Likewise, the electric power output characteristic of the driven machine, when operated at its rated synchronous speed, was examined. It was found that the driving machine performed better on mixed fuel than pure gasoline. There were gradual increases in the torque and the power developed by the machine as the proportion of ethanol in the fuel-mix and the rotational speed increased. While the highest values of torque and power developed on using pure gasoline were 12.4 Nm and 2574 W respectively at 1900 rpm, 13.1 Nm torque and 2953 W power were obtained from the machine when ignited with 10%-bioethanol fuel-mix at the same speed. Also, with 90 Vdc excitation voltage and rotation at 1500 rpm synchronous speed, the driven machine continuously generated electricity at 207.6 Vrms (line-to-line), 1.169 A, 0.698 power factor, 48.17 Hz, 0.294 kW output. This study demonstrated the possibility of continuous generation of electric power from cocoa and kolanut wastes. Result obtained from the laboratory-based trial indicates that at such agricultural regions that are advantaged in the production of the two crops, harvest residues of the crops can be explored as a steady source of biofuel for off-grid microgrid electrification.

International Journal of Emerging Electric Power Systems, Mar 14, 2017

Presented in this article is a scaled model of a hybrid-source autonomous electric microgrid, whi... more Presented in this article is a scaled model of a hybrid-source autonomous electric microgrid, which is developed using a Real Time Digital Simulator, to provide a laboratory-level research facility on renewable energy-based electric microgrid systems. Three energy sources: a pico-hydropower emulator, a diesel engine emulator and a wind turbine emulator; are interconnected at a point of common coupling, with the hybridized source supplying an aggregate of electrical load. A control scheme is developed that employs the synchronous machinebased pico-hydropower emulator as grid-forming source, while the other two sources feed the grid-former. Since models demonstrated with simulated weather data and load demand profiles may not accurately represent the operational behaviours of the actual system in the real-world scenario, a real-life wind speed profile is implemented on the wind turbine emulator to investigate the behaviours of the lab-microgrid under a nearreal-world operating scenario. Balance reactive power flow is established among the three source emulators as a result of which the frequencies of the emulators are synchronized. A proper fault ride-through characteristic is also exhibited by the system. These show that the near-real-world behaviours of the lab-microgrid closely match the operational performance of the actual microgrid in the real-world scenario. The application could, therefore, be adopted as an affordable laboratory tool in research activities and as an instructional kit in teaching on the autonomous microgrid.

Injection of Reactive Power Support for Enhanced Performance of Radial Distribution Network

Tanzania Journal of Engeering and Technology, Jun 30, 2022

This study aims at providing an experimental sizing procedure for a rooftop PV-based solar power ... more This study aims at providing an experimental sizing procedure for a rooftop PV-based solar power system for an engineering laboratory. This was achieved by monitoring the peak power and energy delivered by an installed 20W solar panel into an 18 Ah battery. Knowledge of the average daily peak power and energy was used to determine the percentage rated capacity available for use and the sun hour. A load consumption comparison was also carried out with and without the connection of a load to inverter. In addition to this, the monitoring of the no-load consumption of the inverter was carried out. This was carried-out to ascertain the contribution of the inverter to the system. With the knowledge of the average daily energy deliverable, sun hour and the no-load power of the inverter, a sample sizing for basic electronic laboratory loads was done. The findings of the study reveal that the average available power is 89.35% of the solar panel rated capacity while the average sun hour is 4.38 h. It has also been shown that an approximate difference of 20 W exists between the power consumption of the load with and without its connection to the inverter. This value (i.e., 20W) has been recorded as the approximate no-load power for the inverter. The sample sizing done has shown that, the solar panel energy requirement of the system with inverter may be considerably higher than that without inverter. ARTICLE INFO

Zenodo (CERN European Organization for Nuclear Research), Jun 30, 2022

Distribution systems occupied a core position in the hierarchical structure of conventional power... more Distribution systems occupied a core position in the hierarchical structure of conventional power systems. However, several factors limit the expected efficiency of many practical distribution systems. It is, therefore, a thing of concern to power distribution engineers to seek better ways to manage both the amount of real power loss and deviation on bus voltage profile. On this premise, this paper presents the use of a shunt capacitor as a mitigating device. The initial state of the test case system was determined using the backward forward sweep (BFS) power flow technique. Cuckoo search algorithm (CSA) and voltage stability index (VSI) were employed to site and size the amount of reactive power injection. The proposed approach was tested on IEEE 33 bus system. Simulation results obtained were validated with other optimization algorithms. Results comparison showed that the proposed method outperformed binary particle swarm optimization (BPSO), real coded genetic algorithm (RCGA) and simulated annealing (SA). In a similar vein, system stability also improved as shown in the values obtained for VSI after integrating the shunt capacitor. This approach is therefore capable of strengthening the performance of the radial distribution system.

Energy Sources, Part A: Recovery, Utilization, And Environmental Effects, Oct 3, 2019

Geometrical increase in power demand and high load density at the distribution ends of modern pow... more Geometrical increase in power demand and high load density at the distribution ends of modern power systems have key consequential problems of high power loss and poor voltage profile, as a result of which the integrity of radial distribution networks to faithfully account for the energy received from transmission subsystems has been seriously undermined. This challenge is, however, being overcome by placement of shunt capacitors to supply the reactive power required for compensation; hence, optimal sitting and sizing of compensators has been intensively researched. As efficient as the use of meta-heuristic algorithms for joint optimal placement and sizing of the shunt capacitors are, employment of the approach on the Nigerian radial distribution system (RDS) is not yet popular as most of the earlier works reported rather used analytical and numerical programming approaches. In this study, therefore, the use of firefly algorithm (FA) on a Nigerian 11-kV feeder is presented as an approach to optimally site and size shunt capacitor for real power loss reduction on such network. Backward-forward sweep load flow technique, with voltage stability index (VSI), is employed to find the candidate buses where the shunt capacitors would be installed, then FA is employed to determine the optimal size required. This approach is implemented on a 34-bus 11-kV feeder and it is found out that the system's real power loss reduced from 762.6419 to 597.7486 kW, while the minimum bus voltage magnitude was raised from 0.8295 to 0.8456 p.u. and the minimum system VSI was improved from 0.4741 to 0.5121 p.u. Based on these results, the proposed approach is, therefore, considered a promising technique for sitting and sizing shunt capacitor optimally in real practical RDS.

Electricity Consumers’ Satisfaction During COVID-19 Lockdown in Some Selected States in Nigeria

Jindal journal of business research, Oct 4, 2021

This work studies the satisfaction experienced by electricity customers in Osun, Lagos, and Ogun ... more This work studies the satisfaction experienced by electricity customers in Osun, Lagos, and Ogun States during the recent lockdown occasioned by the COVID-19 pandemic. The measures of the satisfaction are based on the hours of electricity supply during the period, easiness experienced for payment of prepaid bill and swiftness in faults correction of the distribution companies involved. A questionnaire was developed using Google Forms. The form was shared through various online platforms. A total of 274 electricity consumers responded to the questionnaire, but after sorting, 259 consumers across the three states were analyzed. From the responses, majority of respondents claim there was increased hours of supply during the period when compared to before the period. For prepaid customers who had reasons to pay electricity bill, majority claim it was easy paying while most of those who claimed it was not easy was because of their payment method choices, which is using designated points. Majority of those who have reasons for faults to be corrected by the distribution companies claim that there was not promptness in fault correction.

Investigating the effects of faulty induction machine in distribution systems

Scientific African, Sep 1, 2020

Abstract In addition to its use as the workhorse in the industry, induction machines are fast gai... more Abstract In addition to its use as the workhorse in the industry, induction machines are fast gaining popularity in renewable energy applications, hence; the need for continual study on the performances of the machines. In this work, a phase frame analysis of a distribution system that feeds single-phase loads and a three-phase induction motor was implemented with the aim of investigating the effects on the distribution system, of an open-circuit fault that occurs in any of the phases of the stator winding of the motor. The IEEE 4-node test feeder was employed for the study and the phase impedance matrices for all the system components of the feeder determined. A programme based on MATLAB code was employed for the analysis that was done for both the healthy and the unhealthy operating conditions of the machine. Based on a specified voltage tolerance value of 0.00001 V, the simulation converged after five iterations giving relatable and reasonable result. The result showed that an open-circuit fault in any of the three phases of the induction machine resulted in high voltage imbalance that get worsened with increase in single-phase loads connected to the system. It is recommended that the machine be disconnected from the distribution network once such a fault is detected.

Tanzania Journal of Engeering and Technology, Dec 31, 2022

Mitigating power loss and voltage profile problems on radial distribution networks has been a maj... more Mitigating power loss and voltage profile problems on radial distribution networks has been a major challenge to distribution system operators. While deployment of distributed generation, as compensators, has made a suitable solution option, optimum placement and sizing of the compensators has been a concern and it has thus been receiving great attention. Meta-heuristic algorithms have been found efficacious in this respect, yet the use of the algorithms in addressing problems of radial feeders is still comparatively low in Nigeria where analytical and numerical programming methods are common. Hence; the use of genetic algorithm to site and size distributed generator for real-time power loss reduction and voltage profile improvement on the Nigerian secondary distribution networks is presented. Backward-forward sweep load flow analysis, together with loss sensitivity factor, is deployed to identify the buses suitable for the installation of the distributed generation, while the algorithm is employed in estimating the optimum size. This approach is tested on the standard IEEE 15-bus system and validated using a Nigerian 11 kV feeder. The result obtained on the IEEE test system shows 183 kW loss using the compensator, as compared to 436 kW loss without the compensator; while on the Nigerian network the loss with the compensator was 4.99 kW, in comparison with no-compensation loss of 10.47kW. By the approach of this study, real power loss on the Nigerian feeder decreased by 52.3% together with energy cost reduction from N658,789.12 to N314,227.38. Likewise the minimum bus voltage magnitude and the voltage stability index of the network are improved to acceptable limits. This approach is therefore recommended as capable of strengthening the performance of the Nigerian radial distribution system. ARTICLE INFO

UNIOSUN Journal of Engineering and Environmental Sciences, Sep 1, 2019

UNIOSUN Journal of Engineering and Environmental Sciences, Mar 31, 2021

This paper provides a post-deregulation performance assessment of the transmission infrastructure... more This paper provides a post-deregulation performance assessment of the transmission infrastructure of the Nigerian electric power grid using nine years performance profile of eight primary lines of the transmission subsystem. Performances of the lines for the six earliest postderegulation years are evaluated on a three-year basis, taking their performances for the three-year period that immediately preceded the deregulation as a baseline for comparison. Failure counts and outage durations per each line, in the two three-year post-reform periods, are compared to what was obtained in the baseline period. The results obtained show that the deregulation has not yielded significant improvement in the reliability of the transmission network. This indicates that better attention is needed to be given to the transmission assets being at the heart of the power system. Like the privatized assets of the industry, the state-owned Transmission Company of Nigeria must also be properly attended to in order to achieve sustainable development in the Nigerian electric power sector.

Given the importance of the power system security and the role of the operator in enhancing this ... more Given the importance of the power system security and the role of the operator in enhancing this feature, improving the operator's actions and information in the power system management is critical. The proper tools and available information for the operator can continuously improve the power system security. During power system operation, the operator needs to identify probable hazardous contingencies to assess power network security online. Thus, contingency ranking based on their importance has always been of interest to researchers. In present study, a new method is proposed for appropriate contingency ranking and online power network security assessment based on the Phasor Measurement unit (PMU) data. In the proposed method, unlike the previous methods, two voltage and angle indices were used. Since the variables of load-flow studies are used to calculate the proposed index, this index can provide a comprehensive assessment of the network security. The proposed index is implemented on three IEEE 14-, 30-and 57-bus test systems to evaluate its performance. First, using this index, contingency analysis is carried out in 2000 operational points and the obtained results are compared with a randomly selected operating point. The results indicated the performance and response time of the proposed index.

Effects of STATCOM on the critical clearing time of faults in multi-machine power systems during transient stability analysis studies

An ever-increasing size of the power system transmission networks has made the system to be prone... more An ever-increasing size of the power system transmission networks has made the system to be prone to various disturbances which could result to system instability. Therefore, increasing the critical clearing time (CCT) of faults before necessary actions are taken is of paramount importance to power system operators in order to maintain and enhance the dynamic security of the system. This paper takes an advantage of STATCOM device to increase the CCT of a multi-machine power system. The differential and algebraic equation model (DAE) of the system is used. The generator transient model (2-axis model) is also utilized with excitation and governor dynamic models. IEEE 14-bus test system is used in the analysis done in the MATLAB environment. The disturbance introduced is the loss of transmission line. The CCT of the system is determined without STATCOM in place and after which STATCOM is connected across the terminal buses of the critical line and the simulation carried out again. The critical clearing time was found to increase with STATCOM across either of the terminal buses of the critical transmission line.

Journal of Ecological Engineering, Sep 1, 2022

The Southwest Nigeria has witnessed tremendous increase in the output of municipal wastes in the ... more The Southwest Nigeria has witnessed tremendous increase in the output of municipal wastes in the recent years. Non availability of government policy on solid wastes management or its lack of effectiveness where it exists makes unabated open burning the predominant means of municipal solid waste disposal in the region. Open burning of municipal wastes being a major source of anthropogenic air emissions was investigated for atmospheric loading of some hazardous organic pollutants using the emission inventory method. The specific pollutants considered in this study were volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxin (PCDDs) and polychlorinated dibenzo furan (PCDF). The estimated release of VOCs, PAHs, PCBs, PCDD and PCDF from open burning of municipal wastes in the region over the 5-year period investigated were 64000 tonnes, 988 tonnes, 43 tonnes, 0.56 tonnes and 0.2 tonnes respectively. Given the serious human health implications associated with these hazardous organic pollutants, the study suggested conversion of wastes to energy as a possible solution since the region also faces energy challenges.

Energy Modeling and Optimization in a Radio and Television Broadcasting Facility

Turkish Journal of Electrical Power and Energy Systems, May 9, 2022

Agro-Residues for Clean Electricity: In-Lab Trial of Power Generation from Blended Cocoa-Kolanut Wastes

Social Science Research Network, 2021

A Comparative Study on the Performances of Power Systems Load Forecasting Algorithms

Turkish Journal of Electrical Power and Energy Systems, Oct 27, 2021