Análise da influência de harmônicas em relés de sub e sobretensão

Abstract

With technological advancement and the increase in the consumption of electric energy, aspects such as the quality of energy become very important to maintain the stability and security of the electric distribution systems that supply the demand of the population. Harmonic disturbances are becoming more and more present in the network. One of the main causes of this decrease in the quality of energy is the non- linear loads, which make use of power electronics semiconductors. Electronic devices with switched sources or switching elements introduce harmonic distortions. Among some of them we can mention the generation of clean energy by means of photovoltaic panels and electronic equipment that are becoming more and more common nowadays. The presence of harmonics in the electric energy signal alters the waveform of the current and voltage, which can cause a decrease in efficiency of the electrical system and the connected equipment, overloads, noise and anomalies that can damage the devices connected. Relays are widely used as a protection device, having the function of disconnecting parts of the system affected by these anomalies, avoiding the propagation of the disturbances to the rest of the equipment and systems that are interconnected. The objective of this work is to analyze the effects of voltage harmonics on an under and overvoltage relay, with the aim of identifying possible failures in the activation of this protection device.