Study on the Influence of Cellulose Particles Aggregation Degree on AC Breakdown Characteristics of Transformer Oil Gap

Transformer oil is easily contaminated during the transformer operation, reducing the electrical strength of the transformer oil and even leading to sudden transformer failure. Determination of the AC breakdown voltage of transformer oil is included in current standards on liquid dielectrics, which is generally used as one of the maintenance tool for transformers in service. However, these test methods do not consider the effect of contaminant accumulation on breakdown characteristics of insulating oil. In this paper, oil samples with different degrees of aggregation were prepared by applying AC voltages for different times to transformer oil contaminated with cellulose particles and the influence of cellulose particles aggregation degree on the AC breakdown characteristics of insulating oil was studied.