准互易光学电压传感器的电场计算与误差分析

Calculation and error analysis of the electric field for a quasi-reciprocal optical voltage sensor

针对一种新型的具有准互易反射式光路结构的光学电压传感器,设计了基于锗酸铋(BGO,Bi4Ge3O12)晶体横向调制方式的高压探头.采用ANSYS有限元分析软件对所设计的高压探头进行电场计算,得到了探头内的电场及电势分布;讨论了探头内电场分布不均匀及干扰电场导致的测量误差.计算结果表明:标准条件下探头的最高可测电压不低于15kV;电场分布不均匀导致光沿着晶体内不同路径传输时,电场强度对路径的积分结果即测量电压不同,影响传感器的稳定性和测量精度;探头内干扰电场导致0～5 kV范围内最大测量误差达1.2‰,这一测量误差对于2‰精度的电压传感器是不可忽略的.

The optical sensing element in transverse modulation configuration utilizing the Bi4Ge3O12（BGO） crystal was designed for a novel optical voltage sensor with quasi-reciprocal reflective optical circuit.The numerical calculation of electric field was performed using the finite element analysis based software ANSYS and the distributions of both electric field and electric potential were obtained.The influences of the non-uniformity and disturbances of electric field on the accuracy were also analyzed.The simulated results show that the maximal voltage that can be measured is not less than 15 kV at the standard temperature and pressure for the designed sensing element.The integral results of the electric field along different paths are different due to its non-uniformity,which affects the stability and accuracy of the voltage sensor.It can not be ignored for the voltage sensor with the requirement of accuracy 2‰ that the maximal relative measurement error is up to 1.2‰ caused by the disturbances of electric field with the measured voltage from 0 to 5 kV.