Análise do efeito corona para diagnóstico de isoladores poliméricos.

Abstract

The electrical insulation are submitted to electric fields and stress increasing, this occurs due to decreased electrical distances and reducing the amount of materials used in equipments. Corona generates intense electric fields on the surfaces of metal parts causing the degradation of insulating surfaces, especially those made of organic material such as insulators. There is still no consensus on what levels are acceptable corona discharges on the insulating surfaces. Moreover, the intensity of the corona is also affected by degradation of organic insulators. So, the parameterization of the measurements of the intensities of the corona can be used to determine the removal of polymeric insulators operating in an advanced state of degradation. For this, inspection techniques using measurements of partial discharge (PD) in the laboratory, and ultraviolet (UV) light emitted by the corona discharge were evaluated. The UV images were processed to obtain only the region of occurrence of the corona in terms of concentration of píxeis. A correlation between levels of PD and data obtained from the UV camera (discharge points / minute), and image processing (concentration of píxeis in the corona) was performed. Thus, the quantization of the corona technique using image processing was implemented, in which corona levels increase with the degree of pollution and degradation of insulators for small variations in relative humidity.