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[en] In this article, the actual state of the small-scale hydroelectric power plants (PCHs, abbreviations in Spanish) in Colombia in aspects as: Statistic of the water in Colombia, a brief historical review and the characteristics of the PCHs in Colombia, is present. The development PCHs, the executing projects and the actions that has been develop by the INEA (Institute of Nuclear Sciences and the Alternative Energies) is described
[en] The present article describes the various types of hydroelectric utilization, those which defer according to the variables of fall of the water and the accumulation of energy. Also it presents the different structures of civil works, as are: Press, Work of takes, Work of conduct and Central or machines house
[en] A definition of the small-scale hydroelectric power plants (PCHs, abbreviations in Spanish), its classification according to potency and fall and its classification as utilization form is present. The general parameters to PCHs design in aspects as topography studies, geology and geotechnical studies and hydrologic studies are described. The primary elements of a PCH, as dam (little dam), conduction, tank of charge, sand trap (water re claimer), floodgate, grating (network), pressure's pipe, fall, principal valve and turbine are shown. In the study of potential of micro-basins, general points as topography, draining, population, supply and demand of electric energy, morphology, hydrology, geology and hydraulic potential are consider
[en] The hydraulic turbines are defined according to the specific speed, in impulse turbines and in reaction turbines. Currently, the Pelton turbines (of impulse) and the Francis and Kaplan turbines (of reaction), they are the most important machines in the hydroelectric generation. The hydraulic turbines are capable of generating in short times, large powers, from its loads zero until the total load and reject the load instantly without producing damages in the operation. When the hydraulic resources are important, the hydraulic turbines are converted in the axle of the electric system. Its combination with thermoelectric generation systems, it allow the continuing supply of the variations in demand of energy system. The available hydraulic resource in Colombia is of 93085 MW, of which solely 9% is exploited, become 79% of all the electrical country generation, 21% remaining is provided by means of the thermoelectric generation
[en] Colombia has been recognized as the fourth country in the world with high hydraulic resources, the best way to exploit this potential is by talking use of as a main hydroelectric alternative on isolated areas of the country. At the beginnings there was an study the Potential Hydraulic Assessment was performed at the Chicamocha Deep Valley, due to this area count with a good hydrologic and meteorological network enough, to investigate the hydro climate behavior
[en] The Crosshole Injection Test Apparatus has been constructed to evaluate the hydraulic properties and conditions, such as hydraulic conductivity and its anisotropy, storage coefficient, pore pressure etc. within a rock near a drift. The construction started in FY93 and completed on August FY96 as a set of equipments for the use of crosshole hydraulic test, which is composed of one injection borehole instrument, one observation borehole instrument and a set of on-ground instrument. In FY96, in-situ feasibility test was conducted at a 550 m level drift in Kamaishi In Situ Test Site which has been operated by PNC, and the performance of the equipment and its applicability to various types of injection method were confirmed. In this year, a hydrogeological investigation on the single water conducting fracture was conducted at a 250 m level drift in Kamaishi In Situ Test Site, using two boreholes, KCH-3 and KCH-4, both of which are 30 m depth and inclined by 45 degrees from the surface. Pressure responses at the KCH-3 borehole during the drilling of KCH-4 borehole, the results of Borehole TV logging and core observation indicated that a major conductive single-fracture was successfully isolated by the packers. As a result of a series of the single-hole and the crosshole tests (sinusoidal and constant flowrate test), the hydraulic parameters of the single-fracture (such as hydraulic conductivity and storage coefficient) were determined. This report shows all the test result, analysed data, and also describes the hydro-geological structure near the drift. (author)
[en] In developing internal fracture systems in coal beds, the initiation mechanism differs greatly from that of conventional ones and initiations may be produced beyond the wellbore wall. This paper describes the features of the internal structure of coal beds and RFPA2D simulation is used to attest the possible occurrence of initiation beyond the wellbore wall in coal bed hydraulic fracturing. Using the theory of elasticity and fracture mechanics, we analyse the stress distribution in the vicinal coal rock. Then by taking into consideration the effects of the spatial relationship between coal bed cleats and the wellbore, we establish a model for calculating both tensile and shear initiation pressure that occur along cleats beyond the wellbore wall. The simulation in this paper indicates that for shear initiations that happen along coal cleats, the pressure required to initiate fracture for cleats beyond the wellbore wall is evidently lower than that on the wellbore wall, thus it is easier to initiate shear fractures for cleats beyond the wellbore wall. For tensile failure, the pressure required to initiate tensile fracture for cleats beyond the wellbore wall is obviously higher than that for cleats at the wellbore wall, thus it is easier to initiate tensile fractures for cleats at the wellbore wall. On the one hand, this paper has proved the possible occurrence of initiations beyond the wellbore wall and has changed the current assumption that hydraulic fractures can only occur at the wellbore wall. On the other hand, the established theoretical model provides a new approach to calculating the initiation pressure in hydraulic fracturing. (paper)
[en] Dams are built to be highly safe hydraulic works. Nevertheless, they are not exempt from a certain failure risk, which turns in a variable value along the time service of the dam. As the mentioned dam-failure risk can be a significant hazard, analysis on dam-break is becoming important, as same as the assessment of its consequences. This type of studies are intended to reduce the costs linked to dam-failure, which are mainly due to the losses of human beings and material goods. A suitable way to minimize such losses consists of designing emergency plans, which permit to prepare and implant appropriate protection measures. A methodological framework to carry out this kind of emergency plans is introduced in this paper, accompanied by a case study corresponding to an emergency plan of a Spanish dam
[en] This book gives descriptions of basic knowledge of hydraulic, property summary of hydraulic machine, hydraulic pump like types, gear pump, screw pump, vane pump, rotary plunger pump and method of selection of hydraulic pump, hydraulic actuator, hydraulic motor device, accumulator, oil tank, hydraulic power unit, hydraulic fluid, sign for hydraulic circuit, pressure control circuit, speed control circuit, direction control circuit, hydraulic motor circuit and way of selection and use of hydraulic machine.
[en] The prediction of hydraulic fracture height growth is of extreme interest in various engineering practices. To fully understand the dependence of the fracturing height in complex underground geological structures, it is crucial to develop theoretical and numerical hydraulic fracturing models to identify the key variables and their interactions to hydraulic fracture height containment. In this work, we adopt a three-dimensional hydro-mechanical coupling cohesive zone finite element model supported by logging data from a practical engineering project. A novel response surface method with Box–Behnken design is introduced to evaluate the statistical significance of tested variables and to forecast the optimal variable combinations for hydraulic fracture height. The key controlling variables are sorted according to their statistical significance from the analysis of variance, and only the minimum lateral stress ratios in mudstone layer and conglomerate layer are highly statistically significant. The minimum lateral in situ stress contrast is the predominant influence of fracture height containment regarding to their significant negative correlation, while the Young’s modulus contrast is probably not an important parameter in terms of direct control of fracture height. Upon optimization, 41 optimized variable combinations were achieved and could be served as references in regulating this engineering practice or even similar events.