Research On Non-contact Traveling Wave Sensor Based On Electric Field Induction

With the expansion of the power system, and the transmission capacity of transmission lines, the length of transmission line is increasing year by year. Once the transmission line fault, the fault location will be difficult to find, so the research and application of traveling wave fault location method has become a hot topic. The sensor plays an important role in the traveling wave fault location method. Now there are a variety of sensors has been used in traveling wave fault location, but there are still some problems, such as electromagnetic voltage transformer iron core linear range due to the large errors; capacitive voltage transformer secondary side can’t track the voltage change of a side; differential current transformer transient characteristics, susceptible to electromagnetic interference; inconvenient installation of a Rogowski coil was designed in this paper. A based on electric field induction principle of non-contact type traveling wave sensor, application in transmission lines without changing the circuit structure and fault reflection waveform sampling is more accurate.Firstly according to the domestic and foreign on transmission line traveling wave sensor technology research, analysis of the advantages and disadvantages of the existing sensor technology, finally through the metal conductor in the electric field induction ability, selection of aluminum materials design based on electric field induction principle of the non-contact type traveling wave sensor. An equivalent circuit model is established by analyzing the theoretical model of the non-contact type traveling wave sensor. Using simulation and experimental investigation of non-symmetrical structure, symmetry structure distance, area parameter change on influence of fault traveling wave signal sampling precision, sheet metal and measured wire distance more and closer to the diameter of the metal plate fault traveling wave signal sampling the higher accuracy of conclusion, and the influence of medium parameters is higher relative dielectric constant, the fault signal sampling precision higher. Again according to the non-contact type traveling wave sensor sampling signal in the presence of noise and amplitude of a drawback of the filter circuit is designed and attenuation circuit, and through the study of the sampling rate and storage capacity design range 3m~1500m high-speed data acquisition module.Finally set up the experimental measurement system will be non-contact type traveling wave sensor is arranged on the fault location system is tested. According to the results of the tests and data can be seen in this paper, the design of the non-contact sensor of traveling wave fault point positioning is achieved, in which the short circuit and open circuit so avoidance of positioning accuracy are less than 2 meters and on the same fault repeatability of test results were better.