Study Of Continuous Electromagnetic Detection On Buried Pipeline Based On Impulse Excitation

Pipeline transportation plays an important role in the national production and life, it has great significance to guarantee the safety of pipeline transportation. With the increase of service time, a large number of pipelines, especially the buried pipeline are gradually entering the "aging" period with frequent accidents, it is really necessary to repair and replace the pipeline specifically and periodically. Corrosion is one of the main causes of the failure of buried pipeline, to solve the problem, this paper proposes a continuous electromagnetic detection method using impulse excitation which based on the transient electromagnetic method(TEM), that can evaluate corrosion of the buried pipeline with high efficiency and better accuracy by non-excavation.Firstly, the causes of failure of buried pipeline and existing trenchless detection method are introduced in this paper, and the theory of continuous detecting based on impulse excitation, which including the principle of traditional TEM for buried pipeline detection, the characteristic of each signal that generated in the process of detection, the feasibility of continuous detection and the inversion method of residual wall thickness in data processing, etc. Secondly, the influences of parameters of the transmitting coil and the receiving coil in sensor device on the detection results are discussed. Besides, there are two kinds of sensors that add compensating coil and magnetic core are both optimized by theoretical calculations and experiments, and the performance is analyzed. Then, the feasibility, accuracy and efficiency of continuous detection method are verified by comparing the detection results with the fixed-point detection method in the laboratory test environment. Additionally, the factors affecting the results of continuous detection are analyzed and the performance of the sensor which contains magnetic core get verified through the corresponding experiment and discussion. Finally, this paper introduces the detecting process in practical application and illustrates several actual engineering application cases, the feasibility of continuous detection method based on impulse excitation received further verification. This study enriches the trenchless corrosion detection methods of buried pipeline, and has the certain practical significance to guide the safety operation of buried pipeline in service.