Theoretical Study On The Temperature Characteristics Of Optical System Of Optical Voltage Transformer

Traditional voltage transformers cannot meet the development needs of modern power grids due to their ferromagnetic saturation and other shortcomings.The optical voltage transformer(OVT)applies optical sensing principle to overcome the shortcomings of traditional transformers.It can monitor,measure and protect high-voltage power grids,and has good application prospects.Although OVT have developed over the years and have accumulated relative mature theories,their temperature stability has been a key factor hindering their practical application.In order to improve the temperature stability of the OVT,in-depth theoretical research is carried out around the temperature characteristics of the OVT.Based on the existing optical path structure,the optimization is improved.Firstly,in-depth analysis of the theories of the OVT and temperature characteristics of each optical device.On this basis,optical device model and the output model is established according to Jones matrix to deduce thermal induced error and theoretical phase difference of the optical system.Secondly,the method of suppressing the temperature error of the optical system is summarized and the optimization of its structure is proposed around the temperature of the optical system.The method of theoretical derivation and simulation is compared to the electro-optic crystal,the 45 splice point,and the Babinet compensator.Besides,the temperature characteristics of other devices and their effects on the thermal induced error of the optical system are studied.Moreover,the effects of various optical devices on the thermal induced error of the optical system before and after optimization and the compensation effects are compared and analyzed.Finally,the output temperature characteristics of the optical system before and after optimization are simulated and analyzed to verify the effectiveness of the optimized optical system in suppressing temperature errors.The study found that the application of the Babinet compensator optimizes the optical system not only can the birefringence of the electro-optical crystal be compensated,but also the reflective light path can reduce the effect of temperature on the birefringence of the electro-optic crystal.In addition,it is also concluded that the linearity of the output of the optimized optical system is better than that of the optical system before optimization,which is convenient for temperature compensation of the optical system.Correspondingly,the output optical intensity and phase temperature error of the optimized optical system are reduced at a relatively high temperature.Within the range,the accuracy of the 0.1-level error is satisfied,and the temperature stability of the optical system is improved.The research results of the temperature characteristics of the optical system in this paper not only provide a reference for the selection of the device during the actual production process of the OVT,but also lay a foundation for the optimization and improvement of the system structure.The research results show that the optical system optimized by the Babinet compensator improves the output temperature stability of the OVT and has a positive significance for accelerating its practical application.