Analysis And Design Of Fiber-optic Current Transformer Integrated With Power Transformer

With the rapid development of grid voltage level,the traditional electromagnetic transformer gradually exposes to a series of inherent defects such as complex insulation structure,small dynamic range,magnetic saturation.While with the development of intelligent grid,it has gradually been revealed that electromagnetic transformer is difficult to realize the defects of intelligence.In this context,as the representative of the electronic current transformer,the fiber-optic current transformers begin to be applied.However,due to insufficient consideration of the complex operating environment of the primary substation equipment,long-term measuring accuracy and reliabilityand evaluation before put into operation,electronic current transformers exerted in the pilot process sorts of problems,such as poor accuracy and reliability,high fault rate and low integration level with primary equipment,which hinder their massive engineering application.To break the bottleneck of fiber-optic current transformer in engineering applications,the research on product accuracy and reliability enhancement technology,product and power transformer coordination design and comprehensive test verification technology is carried out.System integration and reliable operation of fiber-optic current transformer and power transformer are successfully achieved.Firstly,the technology development and engineering application of fiber-optic current transformers are elaborated.The main existing problems are analyzed.The contents of the paper are put forward.Secondly,the working principle of fiber-optic current transformer is analyzed theoretically using the Jones matrix.On this basis the technology scheme is put forward.Combined with the function realization process,the key factors affecting the performance of the transformer are determined.Thirdly,the structure scheme of fiber-optic current transformer is determined.The key devices’ type are selected for sensor probe,optical unit and signal processing unit.And the main technical parameters of the product are determined.Several accuracy and reliability improvement methods of fiber-optic current transformer are put forward.The design scheme of fiber-optic current transformer and power transformer is designed.Lastly,to test the effectiveness of the design scheme and accuracy improvement,the comprehensive test verification method which combines the independent performance evaluation and the overall performance evaluation is put forward.And the current transformer assessment platform is built to comprehensively examine long-term performance of the product.The third-party test is successfully passed and the reliable integrated operation of fiber-optic current transformer and power transformer is realized.