光学电压互感器中采用高斯算法的误差分析

光学电压互感器具有动态范围大、带宽宽、体积小、重量轻、成本低等优点,是传统互感器的最佳替代产品。针对应用于分布式光学电压互感器的高斯算法相对误差进行研究。虽然权函数的引入使得高斯积分算法具有较高的计算精度,但是权函数并不能完全反映干扰电场的作用,当存在外界干扰时,应用高斯算法计算电压存在一定的相对误差。为此,通过ANSOFT电磁场仿真软件对互感器干扰电场进行相应的仿真,分析了干扰接地平板和相间2种干扰所带来的相对误差,结果表明:对于接地平板干扰模型,干扰电场引起的高斯算法相对误差随平板距离的增大而减小;对于相间干扰模型,AC两相同时接电时对B相电压计算相对误差最大;具有较大相对介电常数的屏蔽材料可以极大改善轴向电场分布,屏蔽管相对介电常数为100时,在1 000mm距离的接地平板干扰以及相间干扰作用下,2点高斯积分方法的相对误差<1.5%。最后分析了屏蔽管尺寸对轴向电场的作用,发现屏蔽管环径较大可以改善电场分布,而屏蔽管内径则对轴向电场分布没有太大影响。

Error Analysis of Gaussian Algorithm in Optical Voltage Transformer

The optical voltage transformer(OVT) has the advantages of large dynamic range,wide bandwidth,small volume,light weight and low cost,and it is the best substitute product for traditional transformer.Consequently,we analyzed the relative error of Gauss algorithm applied to the distributed optical voltage transformer.Introduction of the weight function improved the accuracy of the Gauss algorithm,however;the weight function could not reflect the effect of disturbed electric filed completely,thus,a certain relative error appeared when the Gauss algorithm was applied to calculate the voltage.Therefore,we used an ANSOFT electromagnetic field simulation software to simulate the interference electric field of transformers,and analyzed the relative error caused by the interference grounding flat and interphase interference.The results show that,for the interference grounding flat model,the interference electric field leads to the bigger relative error of Gauss algorithm when decreasing the distance between flats;for the interphase interference model,the calculation of the B-phase voltage will lead to the biggest relative error when the A-phase and C-phase is simultaneously electrified.The bigger relative dielectric constant of shielding material can significantly improve the axial electric field distribution.With the distance of interference grounding flat of 1 000 mm and interphase interference,the relative error of two-point Gauss algorithm is less than 1.5% when the relative dielectric constant of shielding tube is 100.Finally,we analyzed the effect of the size of shielding tube on the axial electric field,and found that the longer ring diameter of shielding tube could improve the electric field distribution and the inner diameter nearly did not affect the axial electric field distribution.