Papers by samuel ezennaya
Sustainability, Apr 26, 2024
Sustainability, Nov 13, 2023
Optimal Power Flow (OPF) with security constraint is becoming increasingly important in the new d... more Optimal Power Flow (OPF) with security constraint is becoming increasingly important in the new deregulated environment of electric power systems as it considers both the normal state and contingency constraints, and therefore is a key function for modern power systems. It is formulated as a large-scale non-convex optimization problem. This paper focuses on the simulation and analysis of the OPF with contingency constraints for the 41-bus Nigerian 330kV power network using Power World Simulator. A prototype of the network was developed in Power World Simulator using the network data sourced from relevant utility companies. Single line contingency were considered. The results obtained show that while the network was stable at pre-contingency state, a lot of violations occurred at the event of some single line contingencies. To maintain security in the face of these credible contingencies, the network generators output were re-dispatched and this resulted in the increase and disparity...
Journal of Electrical Engineering and Electronic Technology, 2017
Investigations are done in this paper to see how Tier-2 compensation technique can expand the pow... more Investigations are done in this paper to see how Tier-2 compensation technique can expand the power systems corridor for the release of embedded transmission capacity. Mathematical models where developed for the savings in power bills, savings in energy and release of systems capacity for extra loadings. The General Steel Mills (GSM) Ltd, Asaba Nigeria was used as a case study to view the effect of locally generated VAr (shunt capacitors) at the buses. These generated VAr corrected the power factors of the load to as close to unity as possible and consequently released the overall systems capacity by 75% with energy and power bills saved to 66% and 23.17Mvar respectively. When this was achieved, the loads being supplied by the transformers was reduced hence the required reactive power by the loads were being supplied at the load locations. These relieve the transformers and the lines of some duties.
Physical Science International Journal, 2017
This work was carried out in collaboration between all authors. Author SOE wrote the protocol, ma... more This work was carried out in collaboration between all authors. Author SOE wrote the protocol, managed the analyses of the study and literature researches. Author SOE did the mathematical design and developed a model that described the input-output relationships and wrote the first draft of the manuscript. Author AS performed the statistical analysis, managed the literature searches and laboratory experiments and implementation. All authors read and approved the final manuscript.
Journal of Electrical Engineering and Electronic Technology, 2017
This work presented a microcontroller based system that can be used in distribution transformer p... more This work presented a microcontroller based system that can be used in distribution transformer protection. The system checked the operating parameters of the transformer (current and voltage) and reported the quantity that was flowing through the transformer. The system was designed such that it was able to detect currents above the normal operating limits (transient currents) and isolated the power transformer from the distribution line. This isolation process was to ensure that the transformer is safe from any excess current (external fault). Excess current causes overheating of transformers and equipment which consequently gets damaged if not controlled. The scheme discussed in this work therefore gave a solution to this problem. It also provided the need to reduce cost of maintenance and ensure that supply of electricity to consumers is not interrupted for a long period. A SET-RESET (S-R) flip flop was used as an interfacing instrument between the power transformer and the circuit breaker emulating the operation of the PIC16F690 microcontroller. This was as a result of the inability of the software adopted toincorporate the controller into the main model. A circuit breaker was used as the switching gears to isolate the transformer from the power system in case a fault. The Scope and Floating Scope of the Simulink model showed current waveforms and indicated the fault currents. It was observed that at a fault of 1.5MVA, the breaker operated at an interval of 0.05 seconds each of two settings of auto-reclosure. While the system returned back to normal after two shots of the reclosure for a transient fault. The auto-reclosure locked-out after exhausting the two setting time for permanent fault. The targeted objective of this project was the effective operation of the auto-reclosure during fault and was confirmed excellent.
For a functional power system, the influence of automatic re-closure on the dynamic stability was... more For a functional power system, the influence of automatic re-closure on the dynamic stability was ascertained by comparing calculated coefficients of system reserves during auto re-closure and without auto re-closure. It is only successful re-closure that was considered using double circuit power line and unsymmetrical short circuit. At the end of the work, a diagram was drawn to illustrate the pickup area Ap and the retardation area Ar. For the calculation of the pickup , retardation and then the coefficient of dynamic stability, there is also the need to find the re-closure angle δr and the re-closure time tr of the affected part. The dependence of re-closure angle on the re-closure time was tabulated. At the end of the investigation, coefficient of reserve of static stability kst at both normal regime and after short circuit regime was compared and found to have ensured higher stability when equipped with auto-re-closure. Lastly, the graph of switch-off angle limit δlim versus sw...
Advances in Science and Technology
In this work , we reviewed the various approaches used in implementing Global System for Mobile C... more In this work , we reviewed the various approaches used in implementing Global System for Mobile Communication (GSM) based wireless control and monitoring systems. The two major methods in use besides various others are Dual Tone Multi-Frequency (DTMF) approach and computer approach that is based on short message service (SMS). The major draw back of DTMF approach is its difficulty in getting feedback besides poor reliability due to network failures. The computer approach solves the problem of feedback and reliability, but is not cost effective and cannot be deployed easily. We propose a Microcontroller-based approach that does not only solve the problems of feedback and poor reliability, but is also cost effective. It presents a protocol that enables the Microcontroller extract every received SMS and utilizes its three major components: the sender, the message, and time of message reception to integrate security and intelligence into the system. This developed protocol can be employ...
Clay and Clay Minerals, 2021
This paper reviewed the production of electric porcelain insulators utilizing from local raw mate... more This paper reviewed the production of electric porcelain insulators utilizing from local raw materials from developing countries. The raw materials used were feldspar, quartz/silica and kaolin. The chemical composition, mineralogy, and thermal properties of the raw materials were characterized using AAS, XRD, and TGA respectively. Different weight percentage combinations of the individual raw materials were investigated by the authors. Most of the results showed relatively acceptable porcelain insulators properties such as low water absorption, porosity, high insulation resistance, dielectric strength and bulk density. The paper showed that electric porcelain insulators with good properties can be produced from available local raw materials in some developing countries using appropriate formulations. However, for production of improved porcelain insulators properties, suggestions were made on the areas for future research.
International Journal of Scientific and Engineering Research, 2015
International Journal of Advanced Computer Science and Applications, 2013
This work proposes Random Power line Synthesis (RPLS) as a quicker computational approach to solv... more This work proposes Random Power line Synthesis (RPLS) as a quicker computational approach to solving RLC parameters of a modern smart grid transmission network. Since modern grid systems provide a holistic perspective of modern grid development, it is obvious that a transmission network that is ageing cannot serve the expanded load demand. The need to revoltionalize the traditional transmission model while exploiting basic electrical theories and principles in Smart Grid (SG) architecture necessitated this paper. This work seeks to address the RLC parameter modelling for SG template to provision dynamic power in Nigerian context. Other schemes of transmission RLC modelling were studied as well as outlining their limitations. Consequently, we then proposed a fuzzy smart grid framework for RLC computation and developed a proposed SG overhead transmission line from its conductor characteristics and tower geometry considering the RLC parameters of the conductor while applying RPLS to generate the parameter metrics.
For a functional power system, the influence of automatic re-closure on the dynamic stability was... more For a functional power system, the influence of automatic re-closure on the dynamic stability was ascertained by comparing calculated coefficients of system reserves during auto re-closure and without auto re-closure. It is only successful re-closure that was considered using double circuit power line and unsymmetrical short circuit. At the end of the work, a diagram was drawn to illustrate the pickup area Ap and the retardation area Ar. For the calculation of the pickup , retardation and then the coefficient of dynamic stability, there is also the need to find the re-closure angle δr and the re-closure time tr of the affected part. The dependence of re-closure angle on the re-closure time was tabulated. At the end of the investigation, coefficient of reserve of static stability kst at both normal regime and after short circuit regime was compared and found to have ensured higher stability when equipped with auto-re-closure. Lastly, the graph of switch-off angle limit δlim versus sw...
ABSTRACT Abstract: with increasing dependence on agriculture, industries and day-by-day household... more ABSTRACT Abstract: with increasing dependence on agriculture, industries and day-by-day household comfort upon the continuity of electric supply from PHCN systems in Nigeria, the forecast of electrical demand have assumed a great importance. For electricity supply not to be an cog in the wheel of progress of the Nigerian economy and perhaps a snag in the attainment of the millennium development goal MDGs load forecasting must be performed to coordinate electricity demand and supply. This research work focuses on Nigeria electricity demand forecast from 2013-2030 towards vision 2025 using Time Series Analysis on past load demand. Index Terms: Commercial demand, Electricity demand, Energy generation, Electricity supply, Energy consumption, Forecast, Industrial demand, Load demand, Residential demand,
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Papers by samuel ezennaya