International Journal of Engineering Research in Africa Vol. 46

Abstract: This paper presents a modified hybrid Controller based on instantaneous power-fuzzy controller (IPFLC) for a shunt active power filter (SAPF). The current produced by the AC source is polluted by harmonics injected by the non-linear loads. The supply system requires filtering by suppressing harmonic currents to improve power quality at interface bus. The filtering system consists of an LC filter and a SAPF. The proposed IPFL Controller for the SAPF is based on a combination of the p-q instantaneous power and the fuzzy logic strategy. In this part, two cases are studied, first the active filter is connected only to a capacitor by its dc side, and second case where the active filter is connected to a photovoltaic source or to a battery. The effectiveness, robustness and the dynamic speed of the proposed controller is validated and assessed using dynamic digital simulation. Digital Simulation results validated also the effectiveness of the active filter scheme with modified controller in reducing the source current THD from 25.87% to 0.83% which largely meets the standards of IEEE STD and International Electro-technical Commission (IEC). Digital Simulation and validation used MATLAB-SIMULINK Software Environment.

Abstract: The rapid growth of the global economy has led to a high demand of electric energy and utilization of fossil fuels to meet the power demand. This has motivated the utilities or independent power providers to incorporate renewable energy resources (RERs) into their power systems. Moreover, with the increasing concerns of environmental protection and fossil fuel depletion, RERS are universally accepted as the potential alternative to fossil fuels. Consequently, this work aims at exploring the application of the photovoltaic (PV), electric storage system (ESS) and wind turbine generator (WTG) in a microgrid (MG) system to reduce the total annual cost (TAC) and environmental impact reduction index (EIR) while maintaining the power system constraints and load requirements. The problem is formulated by using the fmincon optimization solver in the MATLAB environment to assess the environmental and economic effects of utilizing RERs in a MG system. The values of TAC and EIR obtained in the study are compared with the base case study where a reciprocating engine is only utilized to meet the same power demand without using RERs and ESS. The results obtained from the study indicate that a WTG/PV/ ESS/ diesel generator MG system has achieved good results. The outcomes of the study demonstrate that utilization of green technologies is suitable for achieving global sustainable energy development.

Abstract: A Well placement is a well-known technique in the oil and gas industry for production optimization and are generally classified into local and global methods. The use of simulation software often deployed under the direct optimization technique called global method. The production optimization of L-X field which is at primary recovery stage having five producing wells was the focus of this work. The attempt was to optimize L-X field using a well placement technique.The local methods are generally very efficient and require only a few forward simulations but can get stuck in a local optimal solution. The global methods avoid this problem but require many forward simulations. With the availability of simulator software, such problem can be reduced thus using the direct optimization method. After optimization an increase in recovery factor of over 20% was achieved. The results provided an improvement when compared with other existing methods from the literatures.

Abstract: Maintenance management is an orderly procedure to address the planning, organization, monitoring and evaluation of maintenance activities and associated costs. The maintenance management allows to have an efficient tool either to the management of the preventive or curative activity, an optimization of the production tool, and finally a follow-up of the costs and the performances. A good maintenance management system can help prevent problems and damages to the operating and storage environment, extend the life of assets, and reduce operating costs.In this paper, we will first present our model on the joint management of spare parts and maintenance. We will do a simulation study of our model, presented in the first section of this paper. The results of this study are presented in the second section through the presentation of the influence of certain parameters of the model on the operation of the system under consideration. This study carried out on the graphical interface of Matlab, which is one of the performance evaluation techniques. It allows to visualize the variations and anomalies which can be reached in the system considered as an overcoming of the repair of the machines by the unforeseen breakdowns.

Abstract: In this study, airline planning optimization problem based on ferry strategy was considered. Cost was the study objective function subject to forty equality and inequality constraints. Regression analysis as well a genetic algorithm (GA) was used to solve the problem. The mathematical relationship between flight fuel consumption and flight time was established using regression analysis, while GA was used for the optimization. The established mathematical model was used to predict the fuel consumption for the twenty scheduled flight consider based on their respective flight time. The result was found to be satisfactory, as optimal fuel lift plan was achieved in approximately twenty seconds of program run time, as against the large time usually spend using human effort to solve the fuel planning problem. The optimized fuel lift plan was compared with the actual fuel lift plan executed by the airline for the twenty scheduled flight considered. The result revealed thirty percent savings using the optimized plan in comparison to the actual fuel lift plan executed by the airline.