Design And Experiment Study On The Hydraulic Line Monitoring System

The500kV self-contained oil-filled used in Hainan interconnection projectconnecting China Southern power Grid with Hainan Power Grid across theQiongzhou Strait, is the first ultra-high voltage, large capacity, long distancesubmarine transmission line in China. For the oil-filled cable with voltage levelsup to500kV, the insulation conditions determine whether it can operate safety. Soit is important to on-line monitor the insulation status of submarine cable.Submarine cable due to its use of the environment compared to terrestrialcable complexity, which requires a special internal structure, defects and de-ficiencies of the existing technology and detection methods, resulting in its notwidely used in submarine cable monitoring.So far scholars from various coun-tries of the world have been racing to study new means of detection and detectionmethods to be more accurate detection of the submarine cable, but the findingshave not been clear.This reference to the oil-filled cable operation and maintenance manu-al,proceed from the operating principle of the oil-filled cables and terminalcomplement oil equipment,taking into account the practicality and safety ofactual simulation, simulate a set of oil-filled cable equipment in the laboratory,Analysis the impact of the fault gas production oil pressure changes in the oil-filled cable, Simulate typical failure types according to possible failures in therunning cable to draw the relations of cable fault type, duration of action and thecable oil exploded gas production leading to hydraulic changes, completemonitoring of the operation of the submarine cable.In the paper, simulate the electrical aging, thermal aging experiments to theoil-filled cables. Through the cable oil hydraulic line monitoring experimentfound: In the event of a failure of thermal aging, the cable oil decompositiongenerate gas faster, and gas production is also relatively large, so the analog system can monitor the changes in the hydraulic pressure thereby warning thethermal aging failure occurs inside the cable. In the early days of electricityfailure, due to a single point of partial discharge gas production is weak, thedetection system is not very sensitive, so the beginning of the experiment tomonitor hydraulic changes are time cumulative results, but overall, Generalinternal failure of the cable are multi-point and multi-factor combined with theresult of aging, So, the oil-filled cable hydraulic line monitoring system canachieve real-time monitoring of the state of the running cable.