600kV高压标准电容器的研制

Development of a 600kV high-voltage standard capacitor

介绍一种基于压缩SF6气体绝缘的正立式标准电容器的,可测量600 k V工频电压,1 200 k V冲击电压。使用有限元分析软件ANSOFT对高压套管进行仿真计算,套管的接地屏蔽以及中间电位屏蔽的位置和尺寸进行优化设计。中间电位屏蔽上的电压系数k=41.6%时,套管利用率最佳。对于电极的设计,依据电场大小确定高压电极的直径和上下圆弧的尺寸,不断优化屏蔽电极的尺寸,尽可能均匀低压电极表面的电场强度。雷电冲击耐受电压1 440 k V下,装置壳体内部最大电场为18.1 k V/mm。为了改善标准电容器的频率特性,设计时低压电极与外壳内壁的距离仅15 mm。根据标准电容器的尺寸和材料,计算得到温度系数为2.05×10^(-5)/K,600 k V时的电压系数为5.5×10^(-7),偏心引起的电容量变化为3.95×10^(-5),为电极安装之后的固定误差。

This paper introduces an upright type high voltage standard capacitor compressed-gas of SF6, which can measure the power frequency voltage of 600 kV and 1200 kV impulse voltage. The finite element analysis software of ANSOFT was used to simulate the high voltage bushing. The position and size of the grounding shield and the middle potential shield were optimized. While the voltage coefficient k is 41.6% of the middle potential shield, the bushing utilization is the best. For electrodes designing, the diameter and the upper and lower arcs of high voltage electrode are determined by the electric field strength, and we continuously optimize the size of the shielding electrode, the e- lectric field strength of the surface of the low voltage electrode as possible. Under the lightning impulse withstand voltage of 1 440 kV, the maximum electric field inside the device shell is 18.1 kV/mm. In order to improve the frequen- cy characteristics of the divider, the distance between the low voltage electrode and the inner wall of the shell is only 15 mm. According to the size and material of the electrodes, the calculated temperature coefficient of the standard ca- pacitor is 2.05 × 10-5/K, and voltage coefficient is 5.5 × 10-7 with 600 kV voltage. The change of capacitance caused by eccentricity is 3.95 ×10 -5, which is the fixed error after electrodes installation.