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Obadiah N'ang'a, George N, W K, Abungu NO. An experimental Prototype for Low Head Small Hydro Power Generation Using Hydram.. Jomo Kenyatta University of Agriculture and Technology(JKUAT): JKUAT; 2012. Abstractjkuat_conference_paper.pdf

The global rise in energy demand has resulted to the over exploitation of both renewable and non renewable energy sources. Most feasible hydroelectric power (HEP) plants sites have been exploited and the current focus is on harnessing energy from small HEP plants which have low head and flow velocity rendering them unsuitable for HEP generation. Previous research work focused on improving the turbine shape and efficiency; designing better water intake, improving the generator and development of turbines suitable for low heads. The main aim of this research was to optimize the power generated by low head small hydro plants through the use of hydraulic ram pump (hydram) to boost the water pressure before it impinges on the turbine. In the current work, a smallHEP prototype system was designed fabricated and test runs conducted. The prototype comprised of; a low head water reservoir, a hydraulic ram pump which was used to increase the head of the water emanating from a low head source, a high head reservoir mounted at a the most optimal height based on the hydram flow rate and pressure considerations and a double cup pelton wheel turbine suitably designed to extract power from the water jet. A drive pipe was used to connect thehydram pump to the low head reservoir while the delivery pipe connected the pump to the high head reservoir. Water from the high head reservoir was used to turn the pelton turbine which was coupled to a generator. The flow rate in the drive pipe and the delivery pipe as well as the pressurein the hydram were optimized by adjusting the waste valve stroke length. It was observed that the hydram was able to pump water to a higher head which then increased the power produced by the turbine.

Odero AN. A Study of the Electrical Insulation Characteristics of Woods Locally locally available in Kenya. Nelson I, ed. Nairobi: University of Nairobi; 1993. Abstract

For my thesis I did a problem formulation and then wrote a computer program to help speedily analyze various insulator profiles for use at high voltages. The program when fed the profile would output the potential and electric field patterns around the high voltage insulator, in addition to predicting it's flashover voltage. Validation of the model was obtained through practical measurement in a high voltage laboratory. Profiles that would insulate very high voltages were arrived at this way in a relatively short time.

Odero AN. Tariff Development for Kenya. Nairobi: University of Nairobi; 1990. Abstract

For my final year undergraduate project, I developed tariffs for various classes of consumers of KPLC electrical energy using the marginal costing technique. This is a forward looking accounting method that takes into account expansion plans and how the power system is to be operated as demand increases. Expansion plans, which would entail capacity/inestment costs, operation and maintenance costs forecasts, administration and general costs forecasts, total kilowatt costs, and peak and off-peak energy and fuel costs, spring from load forecasts. This resulted in an efficient resource allocation scheme in which power prices to consumers are related to the resource costs of changes in consumption, i.e, the addition of a new consumer or an increase in consumption of an existing consumer will impose additional costs on the enterprise, while a reduction in consumption will save costs. These alteration in costs are the ones that need to be reflected in tariffs. The change in the cost to a consumer of altering his electrical behavior will then mirror the change in the cost to the enterprise. This not only results in fair and equitable tariffs, but also ones that inherently have incentives to better consumption patterns by consumers.

This marginal costing technique contrasts sharply with the accounting (traditional) one which is based on examining the records of past expenditure thus becoming backward looking. Such prorated accounting costs are quite different from the costs relevant to resource allocation and creates the illusion that resources which can be used or saved are as cheap or as expensive as in the past, i.e, resources are as abundant or as restricted as in the past. On the one hand this may cause over investment and waste; on the other, it may lead to under investment and unnecessary scarcity. In addition, if the past holds a number of poor projects, the sunk costs of mistakes, if reflected in prices, will overstate the costs to the consumer of extra consumption, which is not efficient. Tariff schedules and the various simplifications thereof are derived by spreading total accounting costs among consumers. This generates tariffs which relate to average rather than to marginal costs.



Concerted efforts have been made towards developing more elaborate techniques for solving aperture coupling problems. The majority of these techniques, however, deal with apertures of regular shapes and, in each case, only a particular problem has been solved. It is only with the development of numerical methods, such as the Method of Moments and Finite Element Method that it has become possible to treat irregularly shaped apertures.

However, each of the above methods has its own advantages and disadvantages when applied to different problems. The Method of Moments is an integral equation method which handles unbounded problems very effectively but becomes computationally intensive when material and structural inhomogeneities exist. In contrast, the true power of the finite element method is revealed in three-dimensional volume formulations in the presence of material and structural inhomogeneities. The method requires less computer time and storage because of its sparse and banded matrix. The matrix filling time is also negligible when simple basis functions are used. For complex basis functions, the matrix filling time can be significant.

A suitably implemented hybrid method takes advantage of the strengths of the individual methods constituting it while avoiding their weaknesses. This research therefore, as one of its objectives, has developed a hybrid method that combines the method of moments and the finite element method (MOM/FEM). The analysis is based upon the "generalized network formulation" for aperture problems. The cavity region is subdivided into tetrahedral elements resulting in triangular elements on the surfaces of the apertures.

In this work, a hybrid MOM/FEM solution procedure for the general problem of apertures of arbitrary shapes in thick conducting screens and waveguide walls has been developed and used in the analysis of a variety of representative problems. Appropriate modeling of the aperture/cavity has been carried out using tetrahedral and triangular elements. Suitably defined sets of basis functions have been integrated into the formulation which is capable of accurately evaluating fields of apertures of arbitrary shape. The problem has been formulated by invoking the equivalence principles and utilizing boundary conditions on the apertures/cavity to derive equations which have then been transformed into matrices that are then solved numerically by simulation on a digital computer. The finite element method, employing reliable vector formulation, has been employed in the computation of the interior admittance matrix. Here, edge elements or tetrahedra in which the degrees of freedom are assigned to the edges rather than the nodes are utilized. This resulted in the avoidance of nonphysical or spurious modes, a difficulty that arises when node-based elements are used. Based on the preceding formulation, extensive computation of various parameters for apertures/cavities of various shapes has been done and results presented. The two main classes of problems treated in this study comprise apertures of arbitrary shape in thick conducting screens and waveguide-backed apertures.

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