Analysis And Suppression Of Polarization Error In Converse Piezoelectric Optic Voltage Transducer

The optical voltage transformer,a new type of sensor,used in the power system for measurement and protection.It has many advantages,such as small size,lightweight,wide dynamic range,better insulation performance and so on.It is favored by many researchers and has a good application prospect.Although after decades of research,there are still many problems to be solved urgently.Among them,the polarization error caused by temperature,vibration,manufacturing process and other external factors is the main reason that limiting its development and wide application.Based on this,this paper focuses on the mechanism of polarization error and the suppression method of polarization error.The main contents of this paper are as follows:Through the elaboration of the converse piezoelectric effect and piezoelectric materials,the system structure and basic working principle of the converse piezoelectric optical voltage transformer are introduced in detail.And the voltage-sensitive mechanism is deduced and analyzed theoretically.Using the Jones matrix,the expressions of optical devices are established,and the mathematical model of the optical voltage transformer system in the ideal state is established.Based on the working principle of the converse piezoelectric optical voltage transformer,the optical path system is divided into the first reciprocity optical part and the second reciprocity optical part.The polarization error models of each part are established respectively.The influence of each optical device on the optical voltage transformer is analyzed.According to the effect of special fiber splice angle on polarized light in optical path system of voltage transformer,the polarization error models are established,such as the splice angle between polarizer tail fiber and phase modulator tail fiber,the splice angle between Faraday rotator tail fiber and sensing fiber,and the splice angle between sensing fiber and compensation fiber.In addition,the relationship between the polarization error and the length difference between sensing fiber and compensation fiber is analyzed.Based on the polarization error model,the source of polarization error is determined.The polarization error,caused by the first reciprocity optical part and the second reciprocity optical part,is analyzed quantitatively.Based on the line between the phase error and the output error the polarization error caused by the fiber factors,such as the imperfect splice angle and the length difference,is analyzed.It can be seen that the length difference between the sensing fiber and the compensation fiber,based on the polarization error quantitative analysis results,is the main source of the polarization error.A method is proposed to reduce the polarization error by introducing correction value into OVT system using software.The simulation results verified the rationality of the structure of the converse piezoelectric optical voltage transformer and the effectiveness of the polarization error compensation,which laid a foundation for the subsequent design and performance research of the optical voltage transformer system.