电流型EVT传感头的设计及性能分析

Design and performance analysis on the sensor of current-based EVT

介绍了电流型电子式电压互感器(EVT)的结构,并设计了一种应用于电流型EVT的SF6同轴圆筒形电容传感头。研究了传感头的组成原理,并对其电场分布和屏蔽性能进行了仿真分析,结果表明该传感头的绝缘性能满足要求,且具有抗外电场干扰能力强的优点。分析了影响传感头性能的主要因素,其中SF6压力变化造成传感头电容量改变,应通过监测气体压力信号实现误差校正;环境温度变化影响传感器的电极尺寸和电容量的稳定性,应采用低膨胀材料或进行温度补偿;高、低压电极不同轴会产生电容量误差以及影响传感头的绝缘性能,应对其进行严格控制。所作的分析为传感头的制作和应用提供了重要的理论依据。

The configuration of a current-based Electronic Voltage Transformer （EVT） was presented, and a SF6 coaxial cylinder capacitor sensor was designed. The constitution theory of the sensor was researched, and then the simulated analysis on the electric field distribution and its shielding performance were conducted. The simulation results show that the sensor can meet ＇the insulation requirements and has the advantages of resisting electric field interference. The factors affecting the sensor performances were analyzed. The change in the SF6 gas pressure will cause the capacitance variation of the sensor, and the gas pressure signal should be detected to correct the error. The electrode dimension and the stability of the capacitance will be influenced by the variation of the temperature, and the employment of the low-expansion materials or the temperature compensation could reduce the influence of temperature change. The misalignment of the high and low voltage electrodes will lead to the capacitance error and affect the insulation performance, so the misalignment should be strictly controlled. The analysis in the paper pro- vides important theoretical basis for the development and application of voltage sensor.