【摘要】 为掌握SF₆气体的低温放电特性,保证低温环境下SF₆气体设备的运行可靠性。文中开展了-50℃至20℃温度范围内,半球头棒板电极下SF₆气体的工频击穿试验。同时测量了降温过程中SF₆气体的气压随温度的变化。获得了稍不均匀电场中绝对气压0.7 MPa和0.5 MPa的SF₆气体的放电电压随温度的变化规律。发现当温度从20℃降低到-50℃时,SF₆气体的放电电压和气压均呈现先缓慢降低,再迅速降低趋势,放电电压下降趋势的拐点与气压下降趋势的拐点基本一致,计算发现该拐点温度等于SF₆气体的液化温度。利用气体放电理论解释了试验现象,指出SF₆气体液化使气体密度降低从而导致其放电电压降低。进一步计算了SF₆气体的液化温度与气压的关系,为SF₆气体设备在低温下的安全运行提供了参考。更多还原

【Abstract】 In this paper,the power frequency breakdown test of SF₆ gas at hemispherical rod plate electrode at the temperature ranged from-50 ℃ to 20 ℃ is performed for the purpose of mastering the low temperature discharge characteristics of SF₆ gas and assuring the operation reliability of SF₆ gas equipment in low temperature environment. At the same time,the variation of SF₆ gas pressure with temperature is measured. The variation law of discharge voltage of SF₆ gas at absolute pressure at 0.7 MPa and 0.5 MPa in the slightly inhomogeneous electric field with temperature is obtained. It is found that when the temperature decreases from 20 ℃ to-50 ℃,the discharge voltage and pressure of SF₆ gas show the tendency of initially slow decrease and then fast decrease. The inflection of discharge voltage decrease tendency is basically identical to that of gas pressure decrease tendency. It is found by calculation that the temperature of the inflection point is equal to the liquefaction temperature of SF₆ gas. The test phenomena are explained by gas discharge theory. It is pointed out that the density of SF₆ gas is reduced by its liquefaction,thus causing the reduction of its discharge voltage. Furthermore,the relationship between the liquefying temperature and the pressure of SF₆ gas is calculated,which provides a reference for the safe operation of SF₆ gas equipment at low temperature.更多还原