Análisis de la estabilidad de la potencia de aerogeneradores en micro redes eléctricas aisladas

Abstract

During the last 3 centuries, humanity has focused on the production of electrical energy using fossil fuels. This method of electricity production requires the extraction of these fuels by drilling into the ground and subsoil for subsequent combustion, generating greenhouse gases that have a great impact on the environment. In order to reduce this impact, work has been done on the development of clean and renewable energy conversion techniques (that is, non-polluting and inexhaustible) for the production of electrical energy. One of the main natural resources that has been used for the production of electrical energy is the wind, which is called wind energy. For this purpose, different devices called wind turbines have been developed whose function is to transform the kinetic energy of the wind into electrical energy. Wind turbines, or wind generators, can be classified according to the position of the turbine shafts. There are vertical axis wind turbines (VAWT) and horizontal axis wind turbine (HAWT). They can also be classified according to the number of blades, ranging from 2 to 6 blades; according to their speed, such as fixed speed, partially variable speed, variable speed with partial frequency converters and variable speed with complete frequency converters. Finally, wind turbines can also be classified according to the type of generator, which can be a synchronous generator, a permanent magnet generator, a wound rotor synchronous generator (WRSG) or an induction generator\cite{b3}. Thanks to these devices it is possible to generate electricity, store it, inject it into the electrical grid (interconnected systems), or even supply electricity to remote places without access to the electrical grid (isolated systems) such as country houses, livestock facilities, etc. An important factor to take into account in the generation and distribution of electrical energy is to guarantee the quality of the service. Quality is understood as delivering to the user a signal with certain defined and pre-established parameters. In the case of electricity generation from wind energy, one of the factors with the greatest impact on the quality of service is the variation in wind speed. As the power output of the wind turbine is proportional to the cube of the wind speed, a small variation in the wind speed implies fluctuations in the power output. Likewise, variations in wind speed, and therefore in the speed of rotation of the turbine, generate variations in the frequency of the signal that is delivered to the network. This makes it necessary to develop and implement mechanisms to reduce the impact of disturbances on the quality of the electrical energy produced.