500 kV压缩气体标准电容分压器的研制

Design of a 500 kV Compressed-gas Standard Capacitive Voltage Divider

传统的电容分压器由于高低压臂的结构和材质不同,难以保证其分压比的稳定性,为此研制了一种基于平板电极结构的集中式标准电容分压器,该分压器的高低压臂电容电极采用同种金属极板材料,并处于压缩SF_6气体绝缘介质中,可以保证分压器高低压臂电容温度系数、电压系数等特性参数的一致性,进而保证电容分压器分压比的稳定性。采用理论计算及仿真分析相结合的方式确定了标准电容器各部分的尺寸,针对分压器绝缘外筒表面上电压分布不均匀的情况,在分压器内部加设多层均压电极后改善了绝缘套管上的电场分布情况。经实际测试,标准电容分压器高压臂电容量及分压比实测值与理论计算值十分接近,其高压臂电容量电压系数优于1.5×10-5,分压器线性度优于1.0×10-4,可以作为标准电压分压器使用。

It is difficult to ensure the stablity of divider ratio of high-voltage and low-voltage arms of the traditional capacitive voltage divider due to different structures and materials. Consequently, we developed a compressed-gas centralized standard capacitive divider based on standard capacitor. The high-voltage and low-voltage arms using the same metal plate material were placed in the compressed SF6 to ensure the consistency of temperature coefficient and voltage coefficient for the divider. By calculation and simulation analysis, we determined the combination of the various parts of the standard capacitor. According to the uneven voltage distribution on the surface of the insulating outer cylinder, several multilayer uniform electrodes were used in the internal voltage divider. Actual tests show that the measured value of the high-voltage arm capacitance and the divider ratio of the standard capacitive voltage divider are very close to the theoretical calculation values, the voltage coefficient of the high voltage arm is better than 1.5×10-5, and the linearity of the divider is better than 1.0×10-4, which can be used as a standard voltage divider.