光学电流互感器中线性双折射与法拉第效应的分离检测

分析了线性双折射对光学电流互感器(OCT)电压输出的影响,指出了差除和信号处理方案检测输出光信息的不完备性问题,用琼斯矩阵理论证明了差除和方案不能独立检测块状玻璃传感头中线性双折射的结论。提出了光学电流互感器的椭偏检测方案,从椭圆偏振光参量方程出发,推导了温致线性双折射、法拉第旋转角与输出椭圆偏振光椭率、倾角之间的解析式,证明了椭偏检测法对输出光信息检测的完备性,实现了温致线性双折射和待测电流的同时测量。为保证实时性,提出了输出椭圆光的三态检测方案,采用水平、垂直和45°三个偏振态的实时检偏,既克服了线性双折射的影响又实现了待测电流的实时测量,从检测原理上解决了温致线性双折射对光学电流互感器的影响。

The Separate Detection of Linear Birefringence and Faraday Effect in Optical Current Transformer

The effect of optical current transformer (OCT) output voltage for linear birefringence is analyzed, it's incompleteness problem of the examination of output light's information in the difference divided by addition detection system is pointed out, linear birefringence in bulk-glass optical current sensing head cannot be examined separately by the difference divided by addition examination system, it's proved and concluded theoretically by Jones matrix. Bringing forward the elliptical-polarization detection system of OCT, the formula to explain the relationship among the thermal induced linear birefringence, Faraday rotation angle, output elliptically polarized light's ellipticity and obliquity are deduced which are based on the elliptically polarized light parameter formula. The elliptically polarization examination system's completeness for the examination of output light's information is proved, and the thermal induced linear birefringence and electrical current intensity can be tested in the same time. The output of the 3-state detection, horizontal, vertical and 45° 3 polarization state testing are brought forward for ensuring being in real time. Linear birefringence's effect is conquered and electrical current intensity can be tested in real time, the thermal-induced linear birefringence's effect on optical current transformer is solved theoretically.