Simulation on Far Field Eddy Current Detection on Condenser Tube Groups in Fossil Power Plants (II)

Condenser tube tubes are widely applied in condenser in thermal power plants. Leakage often occurs in condenser tube groups due to the quality of condenser media or high serving stress. Condenser tube leakage not only brings economic losses to power stations, but even influences the safety operation of the power generation units. This paper simulates and experimentally studies the ferromagnetic heat exchanger tubes based on the detection mechanism of far field eddy current. The results show that the position of the far field is with the increase of the wall thickness and the inner diameter of the tubes, and the detection sensitivity of the far field is high for the same size defect, but the difference of the magnetic flux intensity varies equally when the defects with the same size are located at the inner and outer walls. This is consistent with the experimental results of real tube defect detection and meets the principle of far field eddy current detection. It is concluded that far field eddy current testing technology can better determine and identify ferromagnetic tube defects, and has a good application prospect for online nondestructive testing and safety performance evaluation of service tubes