光学平衡桥式电流互感器的设计

为了消除传感头随温度变化的线性双折射对光学电流互感器性能的影响,提出了光学平衡桥式电流互感器的概念,并给出了设计原理.推导了与温度有关的线性双折射导致的线偏振光方化角变化量的解析式,并计算了用1/2波片来消除线性双折射影响时波片光轴的方向.给出了光学平衡桥的工作原理和信号处理的方法,推导出计算电流的表达式.进行了实验研究,螺线管电流为2 A,温度在20℃-65℃范围变化时,所设计互感器的输出误差在2.96%以内.提出的光学平衡桥式电流互感器,解决了原有方法存在的线性双折射随温度变化对测量精度影响的难题,有利于促进光学电流互感器的实用化进程.

Design of Optical Balanced Bridge Current Transformer

In order to eliminate the effect to the optical current transformer by the liner birefringence which changes with the temperature, the idea of optical balanced bridge current transformer is advanced, and the principle is also givens analytical expression of azimuth angle variation is deduced that is produced by liner birefringence, the direction of 1/2 wave plate axis is also calculated which is used to eliminate the effect of the liner birefringence. The working principle and signal processing method of the optical balanced bridge are given, the expression that used to calculate the current is deduced. It is proved that the current transformer output error is within 2. 96% when the temperature changes between 20 ℃ and 65 ℃ as the current is 2 A. The advancement of optical balanced bridge current transformer solved the problem of the effect to the system produced by the birefringence along with the variation of temperature which could not be solved using the traditional methods. This new method will boost the utility of optical current transformer.