湿度是影响导线电晕起始电压的重要因素,基于四热阻换热模型和分形理论建立适用于高湿度条件下导线的凝露分布模型,计算得到不同湿度和导线温度配合下导线表面凝露的尺寸和分布规律,计算结果与金相显微镜下凝露试验测量结果相差很小.通过有限元方法由凝露分布模型得出的参数计算得到凝露时导线表面的电场分布;代入导线电晕放电的光电离模型计算得到电晕起始电压的预测值.研究表明:相对湿度越高,导线温度与环境温度相差越大,电晕起始电压下降越明显,在相对湿度高于80%后,电晕起始电压趋于饱和.试验得到的不同凝露条件下导线的电晕起始电压和预测值的误差小于5%.因此,所提方法可应用于高湿度条件下导线电晕起始电压的预测.%Humidity has a significant influence on the corona onset voltage of conductor. The presented paper constructs a condensation-distribution model based on quadri-thermal resistance heat transfer model and fractal theory under high humidity circumstance, and calculates the dimensions of the maximum dewdrop and the distribution regularities of dewdrop under various conductor temperature and humidity conditions, which are agree with the test results of metallographic microscope. The parameters derived from the condensation-distribution model are used to calculate the electric field intensity distribution of conductors, and input the results of electric field intensity distribution into a corona photoionization model to obtain the corresponding corona onset voltage. The higher of the humidity or the temperature differences between conductor and circumstance, the smaller of the corona onset voltage, and when the relative humidity reaches 80%, the corresponding corona inception voltage tends to saturate. Comparing the prediction results of corona onset voltage with experiments results, the errors are less than 5%. Therefore, the proposed method could be applied on the corona onset voltage prediction of conductors under high humidity circumstance.
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