Showing papers by "Kanzumba Kusakana published in 2023"

Combined Generation and Transmission Expansion Planning Model for Improved Modern Power System Resilience

Abstract: Abstract In recent times, the power grid composition is changing as more renewable energy generators and energy storage systems are being integrated. This in turn influences the dynamics of the new grid as frequency instability sets in due to declining system inertia. It is therefore important to properly select renewable energy generators and energy storage units to mitigate frequency instabilities, particularly during times of system contingencies. This study therefore, proposes a new deterministic generation and transmission expansion planning model that enhances the frequency stability of the modern grid. Thus, a mixed integer quadratic constrained programming model is developed to minimize emissions, and cost, while maximizing the overall system inertia. The proposed multi-objective model was validated using three case scenarios and tested on a modified IEEE 9-bus test system. The results obtained from the model simulation reveal that the proposed model (case 3) achieves better frequency stability, higher system inertia, and minimized emissions compared to the models in case 1(only economic objective is considered) and case 2(only economic and environmental objectives are considered), however, at a marginally higher cost which justifies the aim of the study.

Impact of Corrosion in Carbon Steel Pipeline of Marine Wastewater Outfall during Electric Power Generation

Abstract: Municipal wastewater is discharged into the sea after undergoing adequate/suitable treatment process. Carbon steel pipes are the most commonly used subsea metal pipes to transport wastewater deep under the sea. These carbon steel pipes experience corrosion which leads to an increased surface roughness. Pipe surface roughness determines the pressure losses as a result of the friction during the flow of fluid within the pipeline. Hence, pressure losses lead to a reduction in fluid volumetric flow rate. At the outlet of the carbon steel pipeline, a significant amount of energy can be generated from discharged wastewater. It can be generated using hydrokinetic turbine coupled to a permanent magnet synchronous generator (PMSG). Hence, the aim of this paper is to investigate the potential impact of corrosion formation within the carbon steel pipe during electric power generation. MATLAB/Simulink tool has been used to develop the model. Hence, different absolute roughness's have been modelled to analyse the potential impact. When the absolute roughness is increased from 44 micro meters to 60 micro meters, this has led to a 0.44% decrease in generated voltage. Hence, both the rotational speed and frequency of the PMSG were also reduced by 5.4% and 3.6%, respectively.

Statistical approaches to assess the performance of domestic air to water heat pumps

Abstract: Air-to-water heat pump (AWHP) is a renewable and efficient technology used in sanitary water heating. This study focused on the employment of statistical methods to compare the coefficient of performance (COP) and electrical energies consumed using 1.2 kW, 150 L split type AWHP and 0.9 kW, 150 L integrated type AWHP, with 0.5 kW as auxiliary electric heater. The COPs and the electrical energies consumed were determined from the controlled volumes of hot water drawn from each tank at different use periods. The average month-day COPs of the specific volumes of hot water from either system were above two. The p-values from the one-way ANOVA (analysis of variance) and the Kruskal–Wallis tests of the groups’ COPs were smaller than 0.01 and showed significant differences at 99% confidence level. The study can assist energy service companies and researchers, to test for statistical differences in the performance among different AWHPs.