Study On Bridging Characteristics Of Cellulose Particles And Effects On Breakdown Voltage Of Transformer Oil

Insulating oil is widely used in transformers as a liquid dielectric.The most widely used insulating oil is mineral insulating oil.However,mineral oil has a great impact on the environment due to its non-decomposing nature.In the production,transportation and use of transformer oil,impurity particles will inevitably be mixed and new impurity particles will be generated constantly.The existence of these impurities will affect the insulation performance of transformer oil to a large extent,and will easily lead to the breakdown of oil gap,which will have a bad impact on the safety of equipment.At present,based on the influence of impurity particles on transformer insulation oil,most of them are aimed at mineral insulation oil,while plant insulation oil and mineral oil are obviously different in molecular composition and physical and chemical properties,Therefore,this paper has carried out the research work in this respect,mainly including:1)Using FR3 plant insulating oil as the research substrate,an experimental study was carried out on the movement process of cellulose particles and the development process of cellulose particles Bridges under the action of dc electric field.Test result according to the observed in the presence of cellulose particles morphology particles into the bridge process can be divided into three different stages,and based on the experimental observation results,established the direct current field FR3 plant cellulose particles in insulating oil,numerical simulation model of the cellulose particles into different bridge phase of dielectrophoresis force was calculated,from the Angle of theory illustrates the cellulose particle movement and the causes of the formation of "fiber Bridges".2)The existence of cellulose particles and moisture is one of the important reasons leading to the reduction of insulation performance of transformer oil.This paper studies the effect of water and cellulose particles on the breakdown characteristics of transformer oil.By setting up the discharge and breakdown platform of FR3 plant insulating oil in the oil gap under dc voltage and ac voltage respectively,and taking the mineral insulating oil test platform under the same condition as the comparison,the influence rules of water and cellulose particles on the breakdown of transformer insulating oil under dc voltage and ac voltage respectively were analyzed.3)This paper has carried out water and cellulose particles of FR3 vegetable insulating oil and mineral insulating oil insulation parameters of the test and research,through the analysis of water and cellulose particles respectively for insulating oil relative dielectric constant and the influence law of dc resistivity,combining theory knowledge,confirming the breakdown influence law of transformer insulation oil.