正极性纳秒脉冲电压下天然酯绝缘油的击穿特性和发射光谱

Breakdown Characteristics and Emission Spectrum of Natural Ester Insulating Oil Under Positive Nanosecond Pulse Voltage

天然酯绝缘油具有优异的电气绝缘性能,是油浸变压器和脉冲功率装置的良好绝缘介质。为了研究天然酯绝缘油在正极性ns脉冲电压下的绝缘特性,考察了针-针电极结构下针电极曲率半径、电极间距对天然酯绝缘油击穿电压的影响以及油中水分体积分数、油温与天然酯绝缘油击穿电压的关系。并利用发射光谱技术对天然酯绝缘油中放电特性进行了光谱诊断。实验结果表明:天然酯绝缘油击穿电压随电极间距的增大而升高,且相同电极间距下其击穿电压随针电极曲率半径的增大而升高;油温升高对天然酯绝缘油击穿电压影响不明显;随着水分体积分数增加,天然酯绝缘油、25号变压器油击穿电压均有所降低,但天然酯绝缘油击穿电压始终高于25号变压器油。天然酯绝缘油击穿发射光谱诊断表明:C原子在击穿过程中表现活跃,在光谱中观察到多条特征谱线;而H原子只发现了1条特征谱线。

Natural ester insulating oil has been considered as a promising liquid insulating medium for oil-immersed transformers and pulse power plant due to its excellent insulating properties. In order to study the insulation properties of the natural ester insulating oil under positive nanosecond pulse voltage, we investigated the effects of the needle curvature radius and distance between electrodes on breakdown voltage of the natural ester insulating oil.Moreover, we discussed the effects of water volume fraction and oil temperature on the breakdown voltage. The emission spectrum technology was used to make a spectral diagnosis for the discharge in the natural ester insulating oil. The experimental results show that the breakdown voltage of the natural ester insulating oil increases with the electrode distance growing. And the breakdown voltage increases with the needle curvature radius increasing at the same electrode distance. But the breakdown voltage is less affected by the oil temperature rising. Both the breakdown voltages of natural ester insulating oil and No.25 transformer oil diminish with water volume fraction increasing, but the voltage of natural ester insulating oil is always higher than No.25 transformer oil. The spectral diagnosis results indicate that C atom shows an active character, and emits many characteristic spectral lines in the discharge. However, H atom only has one spectral line.