Volume 30, No. 4 (2025)

COMPARISON AND EFFECTIVENESS OF SLIP MODE FREQUENCY SHIFT AND SANDIA FREQUENCY SHIFT ACTIVE METHODS FOR ISLANDING DETECTION IN SINGLE-PHASE GRID-CONNECTED PHOTOVOLTAIC SYSTEMS

FADILA BARKAT(1), ALI CHEKNANE(1), JOSEP M. GUERRERO(2), GEORGE CULEA(3), PETRU LIVINTI(3), IOAN VIOREL BANU(3*)

This paper offers a comprehensive comparison for the effects of two most important active anti-islanding detection methods which are the slip mode shift frequency (SMS) and Sandia frequency shift (SFS). The comparison is proved in detail through the simulation of the proposed single-phase photovoltaic (PV) system in the Matlab/Simulink. The obtained results show that islanding operation can be successfully detected and prevented using the studied active methods with adequate values for grid power and local load quality factor. In addition, adequate parameters of each method lead to reduce the non-detection zone (NDZ) and prevent the failure of the studied methods.

ENVIRONMENTAL LIFE CYCLE ASSESSMENT OF SMOKED FISH PRODUCTION: A CASE STUDY OF THE UNIVERSITY OF IBADAN FISH FARM

IGOMU BERNARD(*), AREMU ADEMOLA, OMOBOWALE MOBOLAJI

The study aimed to carry out a life cycle assessment (LCA) of the production and processing of smoked fish using the University of Ibadan Fish Farm as a case study to identify environmentally detrimental production and processing hotspots. The LCA used cradle-to-gate approach which involves the operations from breeding/hatching to the packaging of smoked fish. Four scenarios were drawn for assessing the impact by varying the energy and material resources. Six impact categories were measured for all four scenarios with Global Warming Potential (0.639 kg CO2-Eqiv.) having the highest impact while Human Toxicity Cancer Effect recorded the least impact (3.463e-11 CTUh). At the end of this LCA study, it was recommended that renewable energy sources as well as energy from bio-waste should be explored for the smoking kilns to achieve cleaner production.

ANALYSIS OF THE INFLUENCE OF CONCRETE AND CLAY SPEED BUMPS ON HEAVY-DUTY TRUCK LEAF SPRINGS

ENOCK ANDREWS DUODU(1) , ISAAC LEGSON MBEAH(1)

This study examines the structural behavior, fatigue lifespan, and damping characteristics of heavy-duty truck leaf springs subjected to concrete and clay speed ramps under various induced loading scenarios. The findings showed that extended leaf springs positioned at the top experience diminished stress levels compared to their shorter counterparts located at the bottom. This research suggests that elongated leaf springs endure substantial bending stress and deformation attributable to the elevation of the speed ramp and the imposed loading capacity, which in turn impacts the fatigue lifespan of the leaf springs under induced loading conditions.

EFFECTS OF SODIUM, POTASSIUM AND CALCIUM CHLORIDE SALTS ON UNDERWATER VISIBLE LIGHT COMMUNICATION PERFORMANCE AND THEIR PRESENCE IN SOME WATER BODIES OF SOUTHWEST NIGERIA

OLAOYE KOLAWOLE(1*) , PONNLE AKINLOLU(1), OJEDIRAN ARIKE(2)

The Salinity is one of the attributes of water that affects underwater wireless optical communication (UWOC) and requires continual investigation. This study investigates the effect of sodium, potassium and calcium chloride salts on transmission of visible light in water via spectroscopy for underwater communication, as well as the presence of these salts in seven water bodies of Southwest Nigeria. Single-salt solutions of each type with varying concentrations were prepared, and their physiochemical properties were measured, as well as their visible light absorbance spectra, from which performance of UWOC for each salt solution at three wavelengths was investigated by simulation using OptiSystem. Water samples were taken from three rivers, two lagoons, and the Atlantic Ocean in Southwest Nigeria and the concentration of the three cations and chloride ion in them were measured as well as their absorbance spectra. For the single-salt solutions, higher absorbance at shorter wavelengths was observed with an increase in salt concentration for sodium and potassium chloride solutions, but calcium chloride solution shows higher absorbance towards longer wavelengths. UWOC simulation results showed that the achievable maximum link distance reduces with salt concentration, varies with wavelength, and is least in calcium chloride solution. For the water bodies, the rivers have low values of salinity and absorbance, while high values were obtained for the lagoons and the Atlantic Ocean. Moreover, their average absorbance showed strong correlations with concentration of calcium and chloride ions than with sodium and potassium ions.

TECHNO-ECONOMIC FEASIBILITY AND SENSITIVITY ANALYSIS OF OPTIMAL DESIGN OF HYBRID GRID-CONNECTED MICROGRID CONFIGURATION FOR SUSTAINABLE AND RELIABLE ENERGY

HABIB MUHAMMAD USMAN(1*) , NIRMA KUMARI SHARMA(1), DEEPAK KUMAR JOSHI(1), ADITYA KAUSHIK(1), SURAJ KUMHAR(1), SANI SAMINU(2), ABDULBASID BASHIR YERO(3)

To mitigate greenhouse gas emission and cost of electricity at Mewar University, this study proposes an optimized microgrid design integrating PV solar panels, wind turbines, diesel generators, and grid connectivity, utilizing HOMER software for optimization. The system would purchase 3,827,194 kWh annually from the grid during low renewable output periods and sell 167,761,193 kWh annually during surplus production. This design achieves a levelized cost of energy (LCOE) of $0.00146/kWh and a return on investment (ROI) of 10.1% (approximately 9.9 years), with total component expenditure of $16,207,384, covering capital investments, operations and maintenance (O&M), and fuel costs. Solar photovoltaics contribute 83% of the annual production, with the remaining 17% from the grid and wind turbines, establishing the system as cost-effective and environmentally friendly due to its heavy reliance on renewable energy sources (RES). Comprehensive feasibility, technical, economic and sensitivity analysis confirm the viability of implementing this proposed system.