Research On The Failure Mechanism Of Key Components In The DC Transmission Optical Measurement System

In the ultra-high voltage direct current transmission project,the high voltage converter station will generate a strong electromagnetic field during operation.It will have a serious impact on traditional electrical measurement equipment,and the traditional measurement method will become unreliable.Due to the electrical insulation properties of the optical fiber,it is not susceptible to interference in the presence of high voltage,strong magnetic field,and electromagnetic pulse.The ultra-high voltage direct current transmission project adopts an independent optical measurement system to complete the tasks of voltage,current collection,analysis,preprocessing and transmission required for direct-current control protection.At present,the life cycle of key components in the direct-current light measurement system of each converter station of ultra-high voltage company cannot be predicted,the failure trend is difficult to judge,the operation and maintenance specifications are relatively scarce,and there is a problem of high failure rate in actual operation.It has seriously affected the normal operation of the ultra-high voltage company's direct-current transmission engineering control and protection system.Therefore,the research on the failure mechanism of key components in the direct-current light measurement system can realize the comprehensive diagnosis of the health status and life cycle of the direct-current light measurement system.It can judge its failure trend and achieve the purpose of “advance diagnosis,advance treatment”.It has a very high practical value.In the paper,Research on the failure mechanism of key components in ultra-high voltage direct current transmission optical measurement system is proposed.Mainly completed two parts of the work: Firstly,the influence of external environmental factors on the transmission efficiency of fiber links is studied.Through Zemax software simulation,laboratory experiments and field tests,it is concluded that the external temperature of the fiber link is reduced,the bending radius is reduced,continuous light energy is injected and the uncleaning of the fiber end face will lead to an increase in fiber loss,which reduce the transmission efficiency and service life of the fiber.Second,the influence of external environmental factors on the working state of the remote module is studied.The remote module offline detection system is builded,and the influence of the external environment temperature of the remote module on its working state is studied.It is concluded that as the temperature increases,the amplitude of the pulse waveform of the digital signal output from the remote module decreases,and the rise time,fall time and pulse width of the waveform pulse increase.These changes result in lower reliability of the remote module and an increased in its failure rate.The research in this paper provides guidance for the development of the direct-current transmission optical monitoring system technical supervision system and the preparation of operation and maintenance management specifications.It provides theoretical support for the life cycle management of its equipment,and comprehensively improve the operational reliability of the optical measurement system of the converter station.