Regulations tools to incentivize the use of renewable electrical sources are used worldwide, with different mechanisms. This work evaluates the most used ones, based on experiences across the globe, defining them, evaluating their advantages and disadvantages and their impacts in the cost of electricity, in technology prices and in the change of the power generation mix. The discussed methods are Feed-in tariff, compensation schemes (net-energy metering and net-billing), Renewable Portfolio Standards and Renewable Energy Certificates, subsidies, tendering and fiscal measures. After the regulation evaluation, a brief analysis of the encouraged technologies is performed, analyzing how these tools distort the electricity market and the long-term impacts of encouraging the use of variable and inverter-based generation. Also, it is dedicated some effort in discussing the consequences of many incentives, as seen in Germany, Spain and Brazil.

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The current dissertation project performs a comparative analysis of the transient overvoltages generated during the switching of vacuum circuit breakers. The overvoltage phenomenon for these cases can lead to the insulation failure of the equipment connected to the circuit-breakers, according to several reports in the literature. This phenomenon is associated to intrinsic characteristics of the vacuum circuit-breakers, as the formation of the electric arc in their interior and its interruption, their dielectric strength recovery, in their capacity to interrupt high frequency currents interruption, beyond characteristics from the circuit. Due to the complex and random nature of the transient overvoltage, the necessity of developing tools to reproduce such phenomenon associated to the operational features of the vacuum circuit-breaker arose. This dissertation seeks filling this gap, by developing a model that contemplates the vacuum circuitbreaker behavior for both opening and closing switching, in order to collaborate with the understanding of such phenomenon and in the calculations of overvoltages in the time domain. The developed algorithm was implemented in the software Alternative Transient Program (ATP) by means of the programming language Models. From the preparation of this model and from the choice of a reference experiment, it was possible to analyze the behavior of the proposed model and of the models from the main electrical components present in software to calculate electrical transients, e.g. transformers and cables, which merits and deficiencies are discussed along the dissertation. The research was oriented in searching for results that could be more representative to the validation of the circuit-breaker model when changing the models of the remaining electrical components of the circuit, being the parameters adjustment of the vacuum circuit-breakers performed in order to achieve the results closer to the reference. Finally, conditions to aggravate the transitory and the incorporation of solution to reduce the overvoltage and frequencies of the transients were also simulated.