TRANSFORMADA INVERSA DE LAPLACE APLICADA A PREDICÃO DO DESLOCAMENTO DE FASE EM GERACÃO DISTRIBUÍDA

Abstract

The generation of electric energy using biogas in rural properties has been extensively researched in recent years. There are several studies demonstrating its technical, economic feasibility and benefits to the environment. This type of generation, known as distributed generation (DG), is usually carried out by means of synchronous machines. DG has advantages, however, it can bring some inconveniences such as the risk of feeding a stretch of grid during maintenance (island operation). To prevent this from happening, the DGs must have protections that allow the loss of connection to the grid to be identified. Among the identification methods is the vector jump relay. This device monitors the mains voltage by identifying an islanded operation due to the phase shift that occurs at the time of an islanding. To use it, it is necessary to define the parameters to be adjusted in this relay. This assignment is the responsibility of technicians and engineers working on the project to interconnect the DGs with the distribution networks. There is a lack of a clear method in the literature to guide them in choosing these parameters. This document shows that the phase shift can be predicted by knowing the parameters of the transfer function of the synchronous machine. Applying the Laplace inverse transform to this transfer function, it is possible to obtain the equation in time and thus predict the displacement that occurs right in the first network cycle after the islanding.