Effect of contaminant particles, temperature, and humidity on the dielectric strength of insulating oils

In this work, the behavior of the dielectric breakdown voltage of insulating oils concerning variations in temperature, humidity, and contaminant concentration was established. Tests used electrodes for flat, spherical, and Verband Deutscher Elektrotechniker (VDE) type. The influence of contaminant concentration (cellulose, iron, and copper), humidity, and temperature on the breakdown voltage of the oils was determined through a four-level experimental design. Data collected in the tests were analyzed using Analysis Of Variance (ANOVA). The experimental phase of the research was carried out in the High Voltage Laboratory of Unidades Tecnológicas de Santander. The most relevant results showed that the contaminant concentration is inversely related to the oil breakdown voltage, with copper being the material with the most significant influence on the study variable. Likewise, temperature is directly related to the breakdown voltage level, with the highest levels reached when the test is conducted at 90 °C. For the three types of electrodes used, it is shown that humidity has an inverse relationship with breakdown voltage. In all cases, the highest disruption values are achieved with a moisture of 5 ppm. • Factors such as temperature, humidity, and the concentration of contaminants significantly influence performance. • Among contaminants, copper has the most pronounced negative effect on the breakdown voltage of oil. • Breakdown voltage tends to increase with higher temperatures, reaching its maximum at 90 °C. • The study emphasizes the critical role of controlling temperature, humidity, and contaminant levels in transformer oils to preserve their dielectric strength in practical applications.