Simulation Of Dynamic Process Of Micro-Water Precipitation From Oil-paper Insulation During Cooling Process

The performance of the oil-paper insulation is affected by the internal micro-water content,and the performance of the oil-paper insulation is deteriorated when the micro-water content is increased.Due to the influence of production process and aging factors,there is inevitably the existence of trace moisture inside oil and paper insulation,thus it is very important to study the transmission law of micro-water in oil-paper insulation.At present,the research on micro-water transfer at home and abroad is mainly concentrated in the area above 0 ℃,and this thesis will study the cooling process in low temperature environment.In this thesis,the dynamic process of precipitation of micro-water from the oil-paper insulation during the cooling process is simulated and analyzed,the whole process is divided into two parts: diffusion and precipitation,and the appropriate simulation model and simulation environment are constructed.The process of diffusion of micro-water under different conditions is simulated to explore the effect of temperature and other factors on the diffusion rate.The process of precipitation of micro-water in oil-paper insulation is simulated to explore the law of precipitation of micro-water condensed into ice after low temperature.Finally,the well-designed experiments validate the resulting diffusion rules.The results show that when the temperature is lowered in the low temperature environment,most of the micro-water in the oil-paper insulation precipitates due to the decrease of the water solubility in the oil.The precipitated micro-water condenses into ice in a very short time,and then gradually deposited in the bottom of the tank.Only a small portion of micro-water diffuses into thepaperboard from the oil.The whole process of diffusion and precipitation is affected by temperature.When the temperature decreases,the rate of diffusion of micro-water slows down,and the time of ice made of micro-water sinking into the bottom of the tank increases;When the temperature is low enough,the process of micro-water diffusion tends to be static,and a part of the ice in the tank suspends in the transformer oil because the sedimentation rate is too slow.