Browsing by Author "Bello, Mashood Mobolaji."

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The application of volt/var optimisation on South African distribution power networks.
(2016) Chetty, Dayahalan Thangavelloo.; Davidson, Innocent Ewean.; Bello, Mashood Mobolaji.
Electric power utilities can achieve cost savings by maximizing energy delivery efficiency and optimizing peak demand. Technical losses are influenced by both network impedances and currents. Power flow through distribution components are composed of active and reactive components. The reactive power does no real work, but contributes to the overall technical losses. By the appropriate placement and operation of reactive power compensation devices, reactive power flows could either be eliminated or significantly minimized, thus, inherently reducing technical losses. This research investigation presents a method for reactive power compensation of medium voltage radial networks as a cost-effective approach to achieve loss minimization and voltage regulation improvement. The study addresses the optimal placement of distributed shunt capacitors along distribution feeders. A mathematical formulation is developed to show that there is a specific location for a given size of capacitor bank that produces the maximum power loss reduction for a given load distribution on a network. In the Eskom distribution system, for those networks that are voltage constrained, the application of capacitors will also consider raising voltages to statutory requirements, however at the expense of the power loss reduction capability. The method developed maximizes both voltage and power loss reduction. Switching and control strategies are developed to meet these objectives throughout a day cycle. The methodology was tested on an Eskom distribution medium voltage network by power system simulation. Results obtained of improvements in voltage regulation and feeder losses are presented and discussed. The application of shunt compensation and the associated feeder voltage regulation improvement is an enabler for Conservation Voltage Reduction (CVR) that can be applied for demand reduction during peak times. Control strategies for CVR are presented, to cater for an integrated Volt/VAr solution for distribution networks. Furthermore, an assessment of CVR potential within Eskom Distribution networks is presented. This research forms the inception for a series of studies aimed at incorporating Volt/VAr optimization within Eskom Distribution networks.
A methodology for optimal placement of distributed generation on meshed networks to reduce power losses for time variant loads.
(2015) Malapermal, Sanjian.; Davidson, Innocent Ewean.; Bello, Mashood Mobolaji.
In the 21st century, humanity’s thirst for an energy intensive lifestyle has led to the saturated expansion of the modern day power system. As the power system expands, centralised generation philosophies are rapidly being constrained due to increased technical losses. The inability to balance technical, economic and environmental conventional generation needs place further strain on the power system. This constraint has catalysed the emergence of decentralized renewable energy sources. Distributed generation supplements the electrical needs of a rapidly expanding demand for energy and minimises the adverse environmental impact of fossil fuel power stations. Distributed Generation is defined as electric power generation units connected close to load centres. Distributed generation can be classified according to rating, purpose, technology, environmental impact, mode of operation and penetration. Optimally connected distributed generation have many advantages over classically supplied power systems. Such as reduced power losses, improve voltage support and reliability to the system. Deferring network upgrades by relieving congestion and reducing greenhouse gas emission being some of the benefits of integrated distributed generation. This research delivers an optimal placement method of solar photovoltaic distributed generation on a 56 bus utility network to reduce power losses. Critical electrical factors for optimal placement of distributed generation to reduce power losses are defined. A practical loss optimization technique for optimal placement of distributed generation on meshed networks is defined. The technique follows an approach of ranking, profiling, activating, evaluating and finally selecting the optimally placed distributed resources. The importance of reactive power compensation is examined when integrating distributed generation onto meshed networks. Pre and post distributed solar photovoltaic generation placement shows the worsening phase angles leading to poorer power factors. The research demonstrates the impact of penetration and concentration of distributed generation on power system losses. Highly concentrated placement of non-dispatched distributed generation units lead to increase in power losses. Results conclude that the placement of distributed generation for loss reduction on a meshed power system is optimally located to match load-profiled centres. This research is significant as power utility engineers can now benefit from a wider range of skills to assess the impact of DG connections.
Spatial modeling and dynamics of a photovoltaic generator for renewable energy application.
(2006) Bello, Mashood Mobolaji.; Davidson, Innocent Ewean.
Photovoltaic systems alongside energy storage systems are a recognized distributed generation (DG) technology deployed in stand-alone and grid connected system for urban and rural applications. DG system ranging in size from a few kilowatts up to 50 MW refers to a variety of small, modular power-generating technologies connected to the electric grid, and combined with energy management and storage systems to improve the operation of electricity delivery systems. DG provides solutions to two long standing problems of power system operation: non-availability at all times of sufficient power generation to meet peak demands and the lack of capacity of existing transmission lines to carry all the electricity needed by consumers. Installing DG at or near a customer load can eliminate the need to upgrade existing transmission/distribution networks to handle the extra power requirement. Since these distributed energy systems are inertia-less and possess large time constants (response times), there are significant interactions between these systems, the power converters and the distribution networks. This precipitates new dynamics and control limitations, which are unknown in the conventional electric power distribution networks. To perform effective load scheduling, high performance control and optimal operation of these energy systems require an understanding of the dynamic and steady state characteristics of the DG system. This thesis report presents a mathematical model for a Photovoltaic (PVG) generator system, including the energy-storage system. Laboratory test results for steady state performance analysis using various loads are presented and discussed. It concludes with a fundamental economic evaluation of system.