Cable Protection System Based On POTDR Optical Fiber Sensor

With the increase of urbanization and municipal construction,the accidents of distribution network cable being injured by external forces are increasing gradually.With the rapid development of economy and the development of high and new technology industry,the society has higher and higher requirements on the stability,reliability and high quality of power system.Accidental damage of power distribution network cable not only increases the cost of power system operation and maintenance,but also the sudden interruption of power will seriously disrupt the normal life of residents and cause huge losses to related power enterprises.Therefore,it is of great significance to maintain the stable operation of power system and ensure the safety and reliability of power grid cable.Based on the bad laying environment of distribution network cable such as dark and damp,this paper studies the whole distributed Optical fiber sensing technology based on Polarimetric Optical Time Domain Reflectometry(POTDR).The fully distributed optical fiber sensing technology can transmit the sensing information to the relevant system for further processing in real time by a variety of external disturbances in the sensing area without blind area within a certain space range.The polarized light time-domain reflection technology can obtain the optical pulse vector information,as to perceive a variety of signals generated by the external disturbance,and realize the identification and processing of the type,strength,position and other information of the external disturbance.Based on the above technologies,this paper developed a cable protection system based on POTDR optical fiber sensing,and did the following work:(1)This paper introduces the principle and characteristics of fully distributed optical fiber sensing technology based on polarized light time-domain reflection in detail,and summarizes the characteristics and advantages of optical fiber sensing technology in the field of cable external force damage.At the same time,this paper simulates and analyses the main behaviors of external force damage to cable,and obtains the pie chart of vibration frequency distribution of various behaviors through a large number of simulated external force damage behaviors of cable,which can be used for the system to identify and judge various external force damage behaviors.(2)According to the characteristics of external force damage behavior of cable and the principle of polarized light time-domain reflection technology,this paper presents the basic framework of cable protection system based on the principle of POTDR optical fiber sensing,details the functions and technical principles of each part of the system,and gives the relevant algorithm model,realizing the function of real-time alarm and automatic positioning of external force damage behavior of cable external force damage system.(3)In order to validate the effectiveness of cable force damage protection system,this paper selected three locations in a city to test the system in engineering case analysis,and tested the three indexes of the protection system,including the damage identification rate,response sensitivity and positioning accuracy.After algorithm debugging and model optimization,the system shows good results in engineering cases.