The Research Of Technology Optimization And Quantitative Detection Research On Transmission Line Joints

With the implementation of west-east electricity transmission project, long-distance transmissionsecurity has become increasingly important. The intactness and health of transmission line is thefoundation of transmission security. Magnetic flux leakage (MFL), one of the Electromagnetic NDEmethods, is easy to automate, efficient and has no pollution, high detecting reliability, lowrequirements for environment. With these advantages, it is applied in this paper to transmission linejoint detection.Firstly, this paper describes the principles and typical applications of traditional magnetic fluxleakage testing. Then combined with the structure of the transmission line joints, we propose a newtype of MFL detection method. Based on the electromagnetism theory, partial differential equationsand boundary conditions, using the finite element method, ANSYS Emag is chosen to simulate thenew detect structure.In the numerical simulation, a three-dimensional finite element model of the transmission linejoints is introduced, and its process from element type selection to modeling, meshing, solvingprocess and results processing is expanded. Then defect signal is obtained and the position of sensorarrangement is analyzed. The influence of defect length, lift-off distance, current of exciting coil,distance between two magnetic poles and magnetic permeability for defect signal is also analyzed.The experiments are made and the validity of the model is verified by experimental data.Experimental research on the practice joints and standard LGJ-400/35type high voltagetransmission lines is made, and experimental signal is obtained and processing. Then compared withthe images of two specimens by X-rays, the characteristics of signal is analyzed.Finally, the entire work done is summarized, and some suggestions are given for future research.