Evaluation of Bubble Formation in Transformer Insulation Systems - a Step Forward

Bubble formation in transformers could result in severe consequences leading to power outages and huge financial losses. There is an increased risk of bubble formation in the future due to increasing load demand and much higher loading fluctuations. The bubble formation process in transformer insulation has been studied for decades and the water content in the paper has been addressed as the most influential impact parameter. However, results from the most common insulating material combination of Kraft paper and mineral oil vary widely and a meaningful comparison for other parameters or insulating material combinations is challenging. This paper presents the development and verification of a simple test setup that can be used to study various impact factors on the bubble formation process with a high degree of confidence.</p