一种改善光学电压互感器电光晶体内电场分布的方法

A Method for Improving Electric Field Distribution of OVT's Electro-Optical Crystal

基于线性电光效应的光学电压互感器(OVT)多采用横向调制方式,其晶体内电场分布的均匀性直接影响测量的准确度和稳定性。仿真结果表明,由于晶体内电场分布不均匀,当入射光的角度和位置发生微小偏移时,积分电压误差不容忽视。为了解决这一问题,提出了一种在电光晶体上附加介质的方法,采用Ansoft Maxwell有限元软件对附加介质的BGO晶体内电场进行了仿真计算,结果表明该方法可以有效地改善电场分布,且随附加介质厚度的增加,电场分布的均匀性不断提高并趋于稳定。电光晶体附加介质后,入射光束发生0.5°小角度偏移时引起的误差由0.11%下降到0.04%,位置偏移0.1mm时引起的误差由0.3%下降到0.08%。文中通过实验验证了方法的有效性,明显地改善了晶体内电场的均匀性。

As the optical voltage transformer（OVT）based on linear electro-optic effect often uses the transverse modulation mode,the uniformity of the distribution of electric field in the crystals directly affects OVTs accuracy and stability.Experimental results show that when the angle and the position of the incident light offset,the inhomogeneity of the electric field causes integral voltage error in the optical path.In order to resolve this problem,a new method of attaching the medium to electro-optical crystal is put forward.And an OVT on 110 kV voltage grade is designed based on this method,in which the internal electric field for BGO crystals of additional medium is simulated and calculated with the finite element software Ansoft Maxwell.The results show that the method can improve the uniformity of the electric field.With an increase in the thickness of glass,the uniformity of electric field is improved and tends to be stable.To attach the medium to the electro-optic crystal when the light path has an offset of 0.5°,the error can be improved from 0.11%to 0.04%,and for the offset of 0.1mm,the error can be reduced from 0.3%to 0.08%,an appreciable improvement on the electro-optic crystal edges aggregation effect.