Rendimento de um autotransformador em interface com sistemas fotovoltaicos: estudos e ensaios experimentais

Abstract

The present work proposed to calculate the yield of a 30 KVA autotransformer from the vacuum and electrical resistance tests and, simulating a photovoltaic system, its daily yield in interface with that system. The CC-AC inverters, techniques for reversing the electrical signals generated by the photovoltaic modules, normally present, as output, voltages between phases and neutral phase of 380/220 V, respectively. Although there are converters that output voltages of 220/127 V, these are rarer and consequently have a higher cost. One of the solutions to this problem is the application of an autotransformer, because its cost is lower than the types of inverters located and its performance is higher than that of a conventional transformer. In the autotransformer, however, there are losses that need to be analyzed, because as the energy generation that a photovoltaic system produces is not regular throughout the day, there is a need to understand whether under conditions of variable loads, the autotransformer continues to work in a range acceptable yield of power delivery to the grid. The tests performed are extremely efficient for determining the specific data of the autotransformer. Procedures performed were the empty test and the electrical resistance test, to determine the performance of an autotransformer, observing different levels of current throughout the experiment. Looking at table results, you can see the necessary adjustments from the tests, using a unitary power factor and 0.92. The autotransformer delivered a high daily performance for fractions of loads over 24 hours. For this work, it was concluded that according to the energy being delivered to the autotransformer, coming from a photovoltaic system, if the value of that energy to reach any fraction of the autotransformer's load will result in a satisfactory performance over a period determined.