Floating Metal Particle Motion Characteristics with Shape and Size Variation in the Oil Insulation Under DC Voltage

Liquid insulation may fail on utilizing its functions due to aging. Aging is caused by the presence of materials such as solid particles, oxygen, water, piles of deposits, dirt, and dust. The solid particles in form of copper, aluminum, stainless steel, and other metal materials may cause impurities and lower the value of breakdown voltage. These particles may float in oil and have different motion and breakdown characteristic. This study was conducted with variable on particles of stainless steel as contaminants. Contaminants vary in shape and size, i.e. spherical and elliptical shape particles with different size. This test was carried out by using DC high voltage generation. Video recording was done to capture the movement pattern of floating metal particles with a high speed camera. Nonetheless, CST simulation was running to determine the field value (E) when the particle moves. The results of the tests showed that the smaller the particle diameter, the greater the breakdown voltage value. Furthermore, particle size has an effect on the pattern of movement of floating metal particles. The larger the particles is, the more cycle generated and the faster floating metal particles move.