Research On Partial Discharge Detection Technology Of Cable Joint Defects Based On Pressure Wave

Cross-linked polyethylene(XLPE)cables are most widely used in power cables due to their excellent heat resistance,insulation properties,mechanical properties,chemical resistance,etc.However,due to the concealment of cables and cables,the probability of failure is also higher.high.The failure of the cable intermediate joint is the main cause of frequent cable failures,so its insulation state is very important to the safe operation of the power system.The signal characteristics of Partial Discharge(PD)are an important basis for evaluating the insulation level of power equipment.Research on the partial discharge detection technology for cable middle joint defects will help improve the reliability of power equipment and ensure the safety of power systems.run.This paper has carried out the research on the partial discharge detection technology of the cable intermediate joint based on the pressure wave,and verified the feasibility of the method through simulation calculation and experiment.This paper proposes a pressure wave-based defect detection technology for cable intermediate joints.The generation,propagation and detection of pressure waves in cable intermediate joints are studied and calculated,and the sound absorption coefficients of different material thicknesses at different frequencies are obtained,and the method is suitable for The conclusion of the defect detection of the middle and low voltage cable joints.According to the calculated structural parameters of the cable joint and the mechanism of the pressure wave generated by partial discharge,this paper establishes a simulation model of the cable joint,selects excitation sources of different frequencies for finite element simulation,and obtains the visual simulation results,which shows the pressure in the middle cable joint The amplitude of the wave signal is negatively correlated with the frequency of the excitation source and the propagation distance.According to the simulation calculation and analysis,it can be known that the pressure wave attenuation speed changes with the change of the diffusion distance,and there is a critical point for the attenuation speed change,so as to obtain the optimal detection point for the surface pressure signal of the cable intermediate joint.This paper sets the size of the sample surface pressure wave amplitude to meet the requirements,selects epoxy resin and other materials to make three typical defect partial discharge models for partial discharge tests.By comparing with the high-frequency current signal,it shows that the pressure signal can accurately reflect the partial discharge.Phenomenon,and the validity and reliability of the method are proved through the faulty cable joint test and the live live detection test.As a partial discharge detection method,the method can achieve electrical isolation,and is convenient to carry,can be used as an auxiliary and supplement to the electrical detection method,and has engineering practical significance.