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Browsing Faculty of Engineering by Author "Ajeigbe, Olusayo A."
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Item Enhancing Small-Signal Stability of Intermittent Hybrid Distributed Generations(2020 5th International Conference on Renewable Energies for Developing Countries (REDEC), 2020-01-01) Ajeigbe, Olusayo A.; Munda, Josiah L.; Hamam, YskandarThe variability of large-scale photovoltaic/wind hybrid distributed generation power integrated into the distribution system causes persistent system oscillations. The oscillations result in serious small-signal stability issues when these distributed generation units are not adequately optimised and the network dynamic variables are unconstrained as seen in the existing renewable power allocation planning works. In this paper, planning and design of optimal allocation (sizing, placement) and timing of intermittent renewable energy hybrid distributed generations such as photovoltaic and wind is being investigated with the ultimate goal of maximising the renewable power generated and absorbed into the distribution network within the required smallsignal stability level at a minimum net present value of total cost. The problem is formulated as a stochastic mixed integer linear program where variables related to small-signal stability are constrained. The paper also evaluated the impact of these renewable generation output power variability on the smallsignal stability of the IEEE-24 bus test system using eigenvalues analysis. The results indicate a profound improvement on the small-signal stability of the network, an increase in the quantity of renewable power absorbed and a significant reduction in the costs of emissions and electricity.Item Optimal Allocation of Renewable Energy Hybrid Distributed Generations for Small-Signal Stability Enhancement(2019-11-14) Ajeigbe, Olusayo A.; Munda, Josiah L.; Hamam, Yskandarwind, and biomass takes into consideration the impact assessment of variable generations from PV and wind on the distribution networks’ long term dynamic voltage and small-signal stabilities. Unlike other renewable distributed generations, the variability of power from solar PV and wind generations causes small-signal instabilities if they are sub-optimally allocated in the distribution network. Hence, the variables related to small-signal stability are included and constrained in the model, unlike what is obtainable in the current works on the planning of optimal allocation of renewable distributed generations. Thus, the model is motivated to maximize the penetration of renewable powers by minimizing the net present value of total cost, which includes investment, maintenance, energy, and emission costs. Consequently, the optimization problem is formulated as a stochastic mixed integer linear program, which ensures limited convergence to optimality. Numerical results of the proposed model demonstrate a significant reduction in electricity and emission costs, enhancement of system dynamic voltage and small-signal stabilities, as well as improvement in welfare costs and environmental goodnessItem Renewable Distributed Generations’ Uncertainty Modelling: A Survey(IEEE PES/IAS PowerAfrica, 2021-01-27) Ajeigbe, Olusayo A.; Munda, Josiah L.; Hamam, YskandarRenewable energy distributed generation is reaching an unprecedented level of integration into power generation systems due to its numerous advantages. However, its increased penetration compounds the level of uncertainties being coped with in distribution systems. This aggravates the difficulty in making decisions in the context of large-scale penetration of renewable distributed generations, especially with the intermittent ones. Consequently, the analysis of uncertainty and modelling of the related system parameters is essential. This paper aims to provide a state-of-the-art review on uncertainty modelling approaches for distribution system studies and applications. This work focuses mainly on classifying and comparing the uncertainty modelling approaches and methodologies, presenting mathematical syntax of the methods, as well as the merits and demerits of the modelling methods. This study serves as the knowledge warehouse and selection tool for choosing the most suitable method for various applicationsItem Towards maximising the integration of renewable energy hybrid distributed generations for small signal stability enhancement: A review(International Journal Energy Res. 2020, 2019-08-12) Ajeigbe, Olusayo A.; Munda, Josiah L.; Hamam, YskandarIntegrating renewable energy hybrid distributed generation (REHDG) into distribution network systems (DNSs) has become increasingly important because of various technical, economic, and environmental advantages accruing from it. However, the output power of REHDGs from photovoltaic (PV) and wind is highly variable because of its dependency on intermittent parameters such as solar irradiance, temperature, and wind speed. Such variability of generated power from large-scale REHDGs or load introduces small signal instabilities (oscillations). Meanwhile, different locations of integration and sizes of REHDGs in the DNS affect the system oscillation modes by either improving or depriving the small-signal stability (SSS) of the network. Consequently, a significant number of research has been conducted on the planning of optimal allocation of REHDGs in DNS. In this regard, this paper reviews the existing planning models, optimisation techniques, and resources' uncertainty modelling employed in REHDGs allocations in terms of their capability in obtaining optimal solutions and enhancing SSS of the system. Planning models with optimisation algorithms are evaluated for modelling renewable resource uncertainties and curtailing SSS variables. Researchworks on planning of optimal allocation of these generations attain minimum cost, but were unable to satisfy the SSS requirements of the system. The existing models for the planning and design of optimal timing, sizing, and placement of REHDGs will need to be improved to optimally allocate REHDGs and satisfy the SSS of the DNS after the integration.