Análise de ocorrências no ponto de conexão de geradores fotovoltaicos

Abstract

The present document aims to assess the behavior of a Distributed Photovoltaic Generation Plant facing the electrical occurrences on the network in which it is connected. A bibliographic review was carried out in order to establish and present the theoretical concepts concerning the theme in question, as well as the definition and representation of a Real Physical System to be submitted to evaluation using simulations. As soon as acquiring the data needed for the development of the study. The SIMULINK modeling tool, from the MATLAB software, was used for the elaboration of the model and for the simulation of the occurrences. The assessment events were pointed out according to the protection features existing in the protection of the plant connection, in a way that, three-phase and single-phase short circuits were set in different conditions, as well as islanding conditions, in addition to an initial evaluation of the plant's behavior in steady state. Once obtained the results of the simulations, an analysis of the existing protection system was carried out, in order to assess whether the appointed settings for the protection relays are able to guarantee ideal operation facing the assessment conditions. Finally, it was found out that the contribution of photovoltaic plants to short circuits in the Electric Power System depends on factors such as solar irradiation at the time of the event and the resulting voltage in the inverters' alternating current bar. Thus, it was observed that the resulting current can reach from twice the rated current to small fractions of it. It was also observed that in cases of reference loss of the network voltage, the system does not keep stability, resulting in frequency variations, extrapolating the acceptable limits. Important outcomes for defining a sensitive and selective protection system for these types of generation systems.