Abstract
This study is on variable-speed wind turbines with permanent magnet synchronous generator. Three different drive train mass models and three different topologies for the power-electronic converters are considered. The three different topologies considered are, respectively, a matrix, a two-level and a multilevel converter. A novel control strategy, based on fractional-order controllers, is proposed for the wind turbines. The influence of a converter control malfunction on the harmonic current emissions is studied. The performance of disturbance attenuation and system robustness is ascertained. Simulation results are presented, and conclusions are duly drawn.

Abstract
A transient analysis for two full-power converter wind turbines equipped with a permanent magnet synchronous generator is studied in this article, taking into consideration, as a new contribution to earlier studies, a pitch control malfunction. The two full-power converters considered are, respectively, a two-level and a multi-level converter. Moreover, a novel control strategy based on fractional-order controllers for wind turbines is studied. Simulation results are presented; conclusions are in favor of the novel control strategy, improving the quality of the energy injected into the electric grid.

Abstract
As wind power generation undergoes rapid growth, lightning damages involving wind power systems have come to be regarded as a serious problem. This chapter gives an introduction to lightning phenomena, lightning location systems and important parameters regarding lightning protection. The wind turbine is described and the main characteristics of its components, like the tower, the generator, the blades, and the electrical and electronic equipment, are highlighted. This chapter also introduces fundamentals of risk analysis method based on international standards, and describes how the rolling sphere method can be used to identify the vulnerable points on a structure. Computer tools and simulations using the LPS 2008 computer program are presented and discussed. Finally, wind turbine issues are discussed.

Abstract
This paper presents an artificial neural network approach for short-term electricity prices forecasting. In the new deregulated framework, producers and consumers require short-term. price forecasting to derive their bidding strategies to the electricity market. Accurate forecasting tools are required for producers to maximize their profits and for consumers to maximize their utilities. A three-layered feedforward artificial neural network, trained by the Levenberg-Marquardt algorithm, is used for forecasting the next 168 hour electricity prices. We evaluate the accuracy of the price forecasting attained with the proposed approach, reporting the numerical results from a real-world case study based on an electricity market.

Abstract
This paper provides a practical approach to the unit commitment problem designed to simultaneously address the economic issue of the fuel costs incurred on the commitment of the units and the environmental considerations due to emission allowance trading. A simultaneously address of fuel costs with the emission implies the consideration of a multiobjective unit commitment emission problem. A trade-off between fuel cost and the emission in a way to aid decision-makers concerning emission allowance trading is obtained, due to this practical approach.

Abstract
In this paper, two wind turbines equipped with a permanent magnet synchronous generator (PMSG) and respectively with a two-level or a multilevel converter are simulated in order to access the malfunction transient performance. Three different drive train mass models, respectively, one, two and three mass models, are considered in order to model the bending flexibility of the blades. Moreover, a fractional-order control strategy is studied comparatively to a classical integer-order control strategy. Computer simulations are carried out, and conclusions about the total harmonic distortion (THD) of the electric current injected into the electric grid are in favor of the fractional-order control strategy. Copyright