Cable Fault Location Technology Based On Series Resonance Test Power Supply

Power cables are playing an increasingly important role in the transmission and distribution of electric energy.With the development of cable manufacturing technology,high-voltage and ultra-high-voltage power cables have been used more and more in recent years.With the increase in the use of power cables,the number of failures will inevitably increase.Fast and effective cable fault location is of great significance to improve power supply reliability and reduce power outage time.Traditional power cable fault location equipment is mostly designed for low-voltage cables and medium-voltage cables.Due to the limitations of the equipment's own capacity and voltage level,these fault location methods are used when faced with high-voltage and ultra-high voltage power cable faults with higher breakdown voltage.It is difficult to complete effective fault location.Based on the traveling wave location principle,a new cable fault location is proposed,which uses a series resonance withstand voltage test power supply corresponding to the voltage level of the power cable to break down the cable fault,and collect the voltage traveling wave signal through a non-contact electric field coupling sensor.This technology can effectively solve the problem of high-voltage(35-110kV)and ultra-high-voltage(110-750kV)power cables that are difficult to complete at this stage,and has very important practical value.Analyzed the traveling wave speed,cable wave impedance,and traveling wave reflection and transmission phenomena that may affect the accuracy of fault location in the traveling wave process;according to the characteristics of series resonance withstand voltage test,combined with the principle of electric field coupling sensor,optimize the sensor structure;Use ANSYS finite element analysis software to perform auxiliary calculation on sensor parameters that are difficult to determine,and clarify the transfer function and transfer characteristics of the sensor's collected signal.According to the power supply and sensor structure,the overall block diagram of the fault location method is given.An experimental platform was built to verify the feasibility of the proposed fault location method,the sensor structure was adjusted according to the test results,and the stability of the location results was tested by repeated experiments at different distances and locations.Finally,go to the site to conduct field tests to verify the safety performance and test accuracy of the positioning technology in the actual environment.Through theoretical analysis and practical verification,the feasibility of the proposed cable fault location technology in testing high-voltage and ultra-high voltage power cables for cable faults with higher breakdown voltage is proved;repeated tests prove the proposed cable fault location technology,Can get relatively stable test results;because of the use of non-contact sensors,the entire test system has no direct electrical connection with the high-voltage circuit,so the personal safety of operators can be guaranteed to the greatest extent;the proposed cable fault location technology The cable is used in the handover test,which can greatly improve the speed of cable fault location and meet the needs of fast cable location.It has very important practical significance and application value.