| 1 |
Author(s):
Isioto, N. N., Nwabueze, C. A., Dickson, R..
Page No : 1-8
|
COMPARATIVE EVALUATION OF ENERGY HARVESTING TECHNIQUES FOR SUSTAINABLE ENERGY IN LOW POWER APPLICATIONS
Abstract
Basically, in the field of electronic engineering, small amount of energy is needed to power electronic devices and so batteries have been the conventional source of energy for most electronic devices. These include devices for mobile communication, real time data acquisition, embedded and remote monitoring system applications. Nevertheless, batteries have issues of limited capacity, access to power supply sources for recharging, battery lifetime and replacement among other issues. In essence, with technological advancement in the fields of embedded systems; Ad-Hoc Sensor Networks such as mobile Ad Hoc Networks (MANETs), wireless sensor networks (WSN), Vehicular Ad Hoc Networks (VANETs) and low power electronics such as MEMS and NEMS, have necessitated the need to explore sustainable and ubiquitous forms of energy as an alternative to the conventional battery. There is therefore need for electronic systems to have high energy retention capacity, self energy generating ability and sustainable source of energy for sustained operation. This feat can be achieved by exploring and tapping ambient energy sources such as thermal, light, RF and mechanical energies available in the environment. The process of extracting and transforming energy from the environment into useful electric energy is called energy harvesting (EH) or Energy Scavenging. This paper presents a survey of various energy harvesting techniques and the observable and available promising opportunities offered. It also explored the various sources of energy harvesting available in the ambience, unfolds the corresponding transducers for ambient energy transformation, reveals several transduction techniques and identifies issues and challenges of energy harvesting. The application areas of harvested energy and desirable properties of energy harvesting and application circuits were also enumerated for informed decision making and application to current trends in energy harvesting.
| 2 |
Author(s):
Okorie, U. I., Nsike, O. J. , Adeyi, A. A..
Page No : 9-20
|
COMPARATIVE ANALYSIS OF GRID FRAGILITY INDICES IN THE NATIONAL TRANSMISSION NETWORK
Abstract
Abstract
An analysis of grid fragility of Nigeria’s transmission grid is of vital importance especially in view of high frequency of grid system collapse (an average of thirty-five system collapses per year). The analysis identifies the weaknesses inherent in the grid which makes it possible to make recommendations to improve system robustness and reliability. Load flow analysis was carried out on the Nigerian 31-bus system using the Newton-Raphson iteration method to obtain line stability index and line stability factor which are useful for the purpose of determining the lines to give priority in transmission system planning and grid expansion schemes.
| 3 |
Author(s):
Ogbu, V. I., Okorie, U. I. , Kenneth, C. B..
Page No : 21-29
|
DETERMINATION OF CRITICAL CLEARING TIME IN MULTI- MACHINE TRANSIENT STABILITY
Abstract
Abstract
In this paper, multi-machine transient stability under severe disturbances was analyzed and critical clearing time was determined. Transient system stability, a term applied to electric power systems denotes the behavior of various synchronous machines when the system is subjected to disturbances. An 11-bus network, consisting of three generator buses, five load buses and fourteen transmission lines was analyzed using MATLAB software. Power- flow analysis was carried out using Newton-Ralphson method and the network was thereafter reduced by eliminating all non-generator buses from the admittance matrix. Three-phase fault on transmission circuit with delayed faults clearing were considered for stability threats. During fault condition, if the machine’s rotor angle swings around 90o and decays very rapidly, then the generator is considered stable, but if the rotor angle goes beyond 180o in the first cycle, it is considered unstable. The results indicated that the system is stable, unstable and critically stable when the fault clearance time were, 0.4, 0.8 and 0.524 seconds respectively. Critical clearing time is used in setting the circuit breakers for power systems operations.
| 4 |
Author(s):
Mmonwuba, Nwanneka.
Page No : 30-46
|
COMPARATIVE ANALYSIS OF PAVING TILES PRODUCED FROM PLASTIC WASTES, PALM KERNEL SHELL AND NORMAL CONCRETE
Abstract
Concrete is one of the most widely used construction materials in the world. To ensure sustainability and a reduction in the cost of concrete, the use of renewable agricultural waste materials and plastic materials as aggregates becomes desirable. This paper presents results of a comparative study of the physical and compressive strength of palm kernel shell concrete (PKS) plastic waste(PT) and normal weight concrete (NWC) using Ordinary Portland Cement (OPC) herein called Lafarge Cement(class 42.5N). Palm kernel shells were used as lightweight coarse aggregate in PKS, plastic materials was use as aggregate in plastic waste and granite was used as aggregates for the normal concrete. The study was conducted in accordance with the British Standards (BS 812, 1990; BS 1881, 1996). Three mixes of ratios 1:2:4 ,1:3:3, 1:4 by weight were used in the study. The values obtained for water absorption, aggregate impact, aggregate crushing, specific gravity and Los Angeles abrasion, satisfy the minimum requirements of aggregates for structural concrete as specified in BS 882, 1992. Compressive strengths of both PKS, plastics and normal weight concretes with Lafarge cement evaluated at 7, 14 and 28-days showed that Lafarge cement produced concretes of higher compressive strengths for PKS, plastics and normal weight concrete. In general, the compressive strength of PKS using Lafarge cement compare well with those obtained from other materials used for structural lightweight concretes.
| 5 |
Author(s):
Ogbu, V. I., Okorie, U. I. , Adesanya, O. R..
Page No : 47-57
|
INVESTIGATION INTO DISTRIBUTION NETWORK ENERGY UTILIZATION: IFA COMMUNITY IN UYO AKWA IBOM STATE AS CASE STUDY
Abstract
Energy audit, with emphasis on utilization, is an inspection, survey and analysis of energy flow for energy conservation in a building, system or process to reduce the amount of energy input into the system without negatively affecting the output. Most of the efforts to address the challenges of poor energy availability are focused on generation and transmission with less attention paid to utilization. This work investigated the utilization of electricity in residential areas of a power distribution network in Akwa ibom state with the aim of providing measures to minimize waste and cost of electricity. The methodology involved the use of data from electricity consumers about electricity consumption vis-à-vis the type of the building, electrical appliances in the building and their billing methods. Heating appliances take 58 %, motorized equipment 21 %, ICT equipment 11 % and lighting devices 10 %. Replacing incandescent lamps with ESLs can save 4.13 % energy. If government of Akwa Ibom state, can proscribe incandescent lamps, a saving of 4.13-9.29 % can be achieved. If consumers switch to more energy-efficient motorized appliances, another 21% of energy shall be saved. A government policy mandating the use of prepaid meter billing will greatly conserve energy as it engenders energy-saving culture in consumers.
| 6 |
Author(s):
Nsike O. James, Aliyu, Alhaji Aliyu , Akaiso, Linus. E.
Page No : 58-69
|
INVESTIGATION OF THE RELIABILITY OF OPTICAL FIBRE LINK IN SOUTH-SOUTH NIGERIA
Abstract
This work tends to investigate the reliability of optical fiber link in South-South Nigeria using Globacom as a case study. Data was obtained from the report of network outages due to fiber failures on the link connecting nodes from Network Operating Centre (NOC), troubleshooting faults from fiber field maintenance team to establish Point of Failure (POF), traces obtained from the use of Optical Time Domain Reflect meter (OTDR) for a period of six months (January 2016 to June 2016) and internet protocol/multiprotocol layer switching report on status of Dense Wavelength Division Multiplexing (DWDM) backbone fiber network. From the investigation and research conducted in this work, it proves that fiber optics reliability tends to degrees as fiber failure rate increases. Optical fiber link gradually decreases as mean time between failures decreases and the link investigated percentage availability was 94.19% which fall short of the standard link availability value of 99.99%
