| The power cable joint is the part with frequent faults. Investigation on sensors to realize the online partial discharge detection of power cable joint can help to record the development process of partial discharge and find latent defects in cable joint, thus improving the level of state maintenance of cable accessories and avoiding the occurrence of insulation fault.In this paper, PD original waveforms of tip and air gap defects in cable joint have been detected using broadband impedance, and the mathematical models of the PD waveforms of two defects are established and verified in both waveform and spectrum analysis.Then, the finite integration method is used to simulate the electromagnetic wave propagation characteristics in cable joint, including internal electromagnetic field propagation modes and attenuation characteristics, which can provide the basis for frequency band selection and installation location selection of the sensor. The cable joint integrated sensors model is established, thus the output signal of the sensor can be obtained directly by numerical calculation, by which the sensor structure can be optimized. And the feasibility of modeling method has been verified by experiment.Finally, according to the actual structure of the 110kV cable joint, a built-in partial discharge sensors is designed, and optimized using the finite integration method, and the feasibility of the sensor is verified by experiment. |
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