| The safe and stable operation of power cables is of great importance.The partial discharge detection of cables is an important method to know the operating status of the cables.In recent years,a large number of studies have been conducted on physical phenomena such as sound,light,electricity,magnetism,and heat that accompany partial discharge at home and abroad.However,these research methods have problems of varying degrees,such as low accuracy and inconvenient installation.At present,there is still a lack of convenient,fast and mature methods for online detection of cable partial discharge.Among the more popular detection methods,the pulse current method and the high-frequency ultra-high frequency method have insufficient anti-interference,large volume,and inconvenient installation,while the ultrasonic method encounters the bottleneck of difficulty in locating the fault point in the cable.In view of the above problems,based on the research on the mechanism of cable partial discharge and the ultrasonic propagation mechanism in the acoustic waveguide,this paper proposes a two-dimensional optical Fabry-Perot cavity cable partial discharge online detection study based on Fabry-Perot cavity interference and Poisson’s ratio positioning technology.The specific work of this research is as follows:(1)Analyze the current research status of partial discharge detection,aiming at the shortcomings of existing detection methods,propose a detection method combining sound and light,and design a Fabry-Perot optical fiber sensor probe based on laser interference as the main principle.When a partial discharge occurs in the cable and its accessories,the sensing probe can simultaneously extract the longitudinal ultrasonic wave based on the Fabry-Perot interference cavity and the lateral ultrasonic wave signal based on the cantilever fiber.As a point sensor,the sensing probe can be easily installed in key parts of the power cable to realize online detection.(2)Build a partial discharge ultrasonic detection simulation experiment platform,adopt the detection method of combination of sound and light,can convert the acoustic signal generated during the collected partial discharge into light signal,and detect the partial discharge in real time and the ultrasonic wave generated by the partial discharge.Positioning analysis of partial discharge points.Through the difference of the longitudinal and transverse ultrasonic wave velocity of the partial discharge ultrasonic wave in the solid medium to locate the occurrence point of the partial discharge,and carry out data analysis,establish a semi-quantitative fault location data model.In this paper,through software simulation and laboratory equipment simulation experiments,the sensor probe is designed and made,and the relevant partial discharge ultrasonic detection research is carried out according to the characteristics of the sensor probe,and the local discharge detection is realized.The research results lay the foundation for the practical application of partial discharge detection in the later rail transit power transmission lines and related components. |
