M. Mañana

Energy potential of waste from 10 forest species in the North of Spain (Cantabria).

In this work, the waste from 10 forest species of Cantabria have been characterized from the point of view of energy. The studied species were the waste of: Eucalyptus globulus, Eucalyptus nitens, the hybrid E. globulusxE. nitens, Eucalyptus viminalis, Eucalyptus smithii, Eucalyptus regnans, Eucalyptus gunni, Fagus sylvatica, Quercus robur and Pinus radiata. The leaves were the tree part with the greatest NCV (net calorific value) in all the species. The best results were obtained for the leaves of E. smithii (24.5 MJ/kg), F. sylvatica (22.8 MJ/kg) and E. nitens (22.5 MJ/kg), at minimum moisture. Values around 65,000 MJ per hectare and year were obtained for the Eucalyptus spp., and 47,000 MJ per hectare and year for the P. radiata. The economic-environmental analysis revealed that the use of the forest waste for energy production would mean an approximate annual income of 8 Meuro and would fix the annual CO(2) emitted by the Cantabrian industries at 78%.

Total harmonic distortion decomposition depending on distortion origin

The total harmonic distortion (THD) ratio is a well-known parameter that characterizes the distortion degree at a specific point of the grid. In this paper, a decomposition of the THD will be presented in order to determine the responsibility of the distribution company and the electrical energy consumer for the harmonic distortion measured at the point of common coupling (PCC). For this study, the power quantities proposed in the new Standard IEEE 1459-2000 and developed by L. Czarnecki were considered. The algorithm of the decomposition will be implemented on a measurement platform based on a digital signal processor (DSP). The general structure of the system-hardware and software-are also discussed. Finally, the apparent powers, defined by both L. Czarnecki and the IEEE Standard, are also compared for single-phase and three-phase systems.

Instrumentation and methodology for revision of European flicker threshold

The European standard CENELEC EN 50160 establishes that the severity of flicker caused by voltage fluctuations, under normal operating conditions, will not exceed the long term severity Plt=1 during 95% of the time in one week. This threshold was originally established considering that a lamp with tungsten filament of 60 W and 240 V, produces a flicker perceivable by 50% of the population when it is supplied with a voltage that verifies Plt=1. This work makes an analysis of this threshold, establishing as hypothesis the fact that incandescent lamps have little use nowadays, specially in industrial and commercial environments. In order to make a revision of the current thresholds, we have proposed an electro-optical equipment and the associated methodology. The device simulates the behavior of the eye plus human brain set, avoiding large clinical experiments. A methodology is also proposed in order to characterize the perceptibility threshold of a generic lamp. Finally, the proposed instrumentation and methodology is applied to two types of lamps: incandescent and fluorescent.

Evaluation of Energy Meters' Accuracy Based on a Power Quality Test Platform

Abstract Is it advisable to replace ferraris based meters with electronic meters? The permanence of the electromechanical meters currently in use is often justified on the grounds of their long working life and low price. However, it is well known that they are highly sensitive to external conditions and that many factors can lead to miscalibration. This work attempts to clarify some key points in order to answer the previous question. It reviews the operating principles of energy meters. The behavior of watt-hour meters under nonsinusoidal conditions is also studied. The disturbances considered were harmonics, unbalance and main frequency variations.

Comparison of flicker sensitivity in HPS lamps

The European standard CENELEC EN 50160 establishes that the severity of flicker caused by voltage fluctuations, under normal operating conditions, will not exceed the long term severity Pu = 1 during 95% of the time in one week. This threshold was originally established considering that a lamp with tungsten coiled coil filament of 60 W and 230 V that is gas- filled produces a flicker perceivable by 50% of the population when it is supplied with a voltage that verifies Pu = 1. Other light sources like fluorescent lamps and discharge lamps with ballasts exhibit a different behavior under the same supply conditions. This means that the flickermeter should be different for each type of illumination technique. A test system and a methodology able to measure the optical fluctuation produced by different types of lamps is presented. This experimental platform allows to obtain a correlation between voltage flicker levels and optical flicker perception. It can be considered the first step in the definition of new lamp models and the specification for new electronic ballast design.

Voltage Fluctuations in Lamps and Ballasts

This article shows that lamp aging has a significant correlation with flicker generation. In this research work, a test system and a methodology able to measure optical fluctuation produced by different types of lamps and ballast are presented. This experimental platform provides a correlation between voltage flicker levels and optical flicker perception. This platform can be considered as a first step in the definition of new lamp models. The limits of the severity of flicker caused by voltage fluctuations are defined in Europe by the standard CENELEC EN 50160.

The influence of costs of fossil fuels and nuclear option on the future spanish generation system

A stochastic linear model have been developed to analyze the Generation Expansion Planning in 2013-2032, through the programming language specific to the application GAMS. In this model the nuclear technology has been considered as generation option in several scenarios of costs of the fossil fuels. Also, two of clean coal technologies have been taken into account. The evolution of supply security has been assessed by means the determination of the vulnerability and degree of independence of the generator system with respect to primary energy sources. On the other hand, the determination of the reserve margin and the percentage of the capacity with regulation capability have allowed to analyze the evolution of its reliability. Lastly, the generation mix of smaller total cost and with less emissions of CO2 has also been determined. The final conclusion would be that a generator system should have the biggest possible number of types of generation.

Methodology for the Low-Cost Optimisation of Small-Wind Turbines

The increasing use of small-wind energy has made it necessary to develop new methods that improve the efficiency of this technology. This is best done by considering the interaction between the various components, such as wind rotors, electrical generators, rectifiers and inverters, as opposed to studying the individual components in isolation. Hence, this chapter describes a methodology to increase the efficiency of small-wind turbines (SWTs) equipped with an electrical machine, rectifier and inverter. To achieve this objective, capacitor banks will be connected between the electrical machine and the rectifier. This methodology is motivated by two clear aims. The first one is to operate the SWT with its maximum power coefficient (Cp). The second one is to select the most suitable capacitor bank for each wind speed in order to optimise the energy supplied to the grid.