空气中不同温度下环氧树脂绝缘子表面电荷消散过程的实验研究

Experimental Study on the Decay Process of Surface Charges on Epoxy Insulators Under Different Temperature in Air

表面电荷的消散与绝缘材料的表面电阻率和体积电阻率有关,而温度的变化会影响绝缘材料的表面电阻率和体积电阻率。为了研究环氧树脂绝缘子在不同温度下的表面电荷消散规律,建立了一套测量系统,采用有源静电探头法,对空气中在针板电极下的环氧树脂圆板绝缘子施加直流电压后进行了表面电位的测量。研究结果表明：各种配方的环氧树脂圆板绝缘子在不同温度下的消散过程都近似呈指数衰减规律;环氧树脂圆板绝缘子的表面电荷消散主要通过沿表面消散的方式进行;表面电阻率越高,表面电荷消散速率就越小;套管在实际运行过程中温度会高于常温,在选用环氧树脂材料时,应考虑其在工作温度范围内的电阻率变化,在保证绝缘强度的同时,尽量选择表面电阻率小的环氧树脂材料,以减少绝缘子表面电荷积聚。该研究结果对超大型直流穿墙套管中的环氧树脂绝缘支撑件的工程设计有借鉴意义。

The surface of insulators is prone to generate charges under a DC high-voltage, which impacts the insulation performance of insulators. The rate of surface charges decay is related to surface and volume resistivity of the insulator. Temperature impacts surface and volume resistivity of the insulator. To study the decay process of surface charges on epoxy resin insulators, we designed a set of surface charge measurement device, which could measure the surface charge distribution on insulators under different temperature. The results reveal that the decay process of epoxy resin insulators is similar to exponential decay process and is mainly related to the surface resistivity of insulators; The larger the surface resistivity is, the smaller the rate of surface charges decay will be; Temperature in working bushing is higher than room temperature. In the selection of epoxy materials, the changes in resistivity within the operating temperature range should be considered; Under the premise of ensuring the dielectric strength, epoxy resin materials with smaller surface resistivity should be chosen to reduce the surface charge accumulation on the insulator. The results of this study are of great significance to the design of epoxy resin insulating support in the super-large DC wall bushing.