In order to reveal the influence of operation conditions on flow electrification characteristics in converter transformer

we researched the flow electrification characteristics of oil-paper insulation with the typical plane electrode structure

and discussed the influence mechanism such as temperature

moisture content and excited DC voltage amplitude on streaming current. The experiment results show that the streaming current decreases as the moisture content decreases in the absence of an excited voltage

and it increases as the temperature and oil flow velocity increase in the absence of an excited voltage. The streaming current increases as the excited voltage amplitude and temperature increase

it increases firstly and then decreases as the moisture content increases at a low temperature and a low excited voltage

and it decreases as the moisture content increases at a high temperature or a high excited voltage. The theoretical analysis shows that

in the absence of an excited voltage

the temperature and moisture content can influence the flow electrification characteristics by affecting the ions diffusion coefficient in the insulation paper and thickness of the electric double layer in oil. The excited DC voltage will accelerate the migration velocity of ions in insulating paper

resulting in the significant increment of streaming current in oil-paper insulation at a low moisture content. Streaming current is closely related to the ions concentration and ions mobility in oil-paper insulation. The flow electrification characteristics of oil-paper insulation will be influenced by the variation of temperature and moisture content via different variations of ions concentration and ions mobility in oil and paper.