高海拔与磁场环境下环氧树脂的绝缘破坏

Dielectric Breakdown of Epoxy Resin in High-altitude and Magnetic Field Environment

为研究磁场环境下的绝缘破坏,采用印刷电极方法,将0.018mm厚的铜薄印制在环氧树脂绝缘板试样表面作为实验电极,使用直流高压电源,测试研究了高海拔低气压和磁场环境对环氧树脂小绝缘间隙绝缘破坏的影响。结果表明:随着气压的降低,起始放电电压减小,绝缘破坏时间延长;磁场环境下的起始放电电压比无磁场时低;磁场环境下的绝缘破坏时间依赖于磁力线与试样表面的相对夹角。

Epoxy resin is widely used as insulating spacer in high-altitude regions where the ambient pressure is low, and it is often used under a magnetic field. However, from the reliable and safety point of view, study on dielectric breakdown of epoxy resin under low pressure and magnetic field is deficient. In this paper, epoxy resin laminate on which two copper electrodes were printed was employed to investigate the effects of magnetic field and low pressure on the dielectric breakdown. The experiment was carried out under electric and magnetic field by using a DC power under decreased pressure conditions, the angle between the magnetic field and the electric field was 90 degree, the magnetic flux density was set at 120 mT, 180 mT and 240 mT respectively. The test sample was placed in a decompression chamber, which was made of glass vessel, and the pressure was reduced by a rotary pump to 70 kPa and 30 kPa. Inception voltage and the time to dielectric breakdown were measured in the test. The results showed that with decreasing the pressure, the time to dielectric breakdown increased, the inception voltage decreased. The value of inception voltage was smaller under magnetic field than that of non-magnetic field. The time to dielectric breakdown under magnetic field depended on the relative angle between magnetic field and sample surface. At relative angle less than 90°, the time to dielectric breakdown was shorter in magnetic field than that without magnetic field. At relative angle larger than 90°, the time to dielectric breakdown was longer in magnetic field than that without magnetic field.