The impact of fusion welding in corrosion diagnosis of joint systems using ultrasonic technique

Nowadays the ultrasonic guide wave technique is the most accurate method in defect detection. Defect detection in the joined and continues systems make some measurement problems due to the structure and propagation of ultrasonic waves in these systems that must be considered for obtained accurate results. In this paper we analysis the manner and the effect of welded points in joint systems. For this aim we specially considered the grounding grids as a joint system and study the problem of the ultrasonic waves in corrosion diagnosis of this system. The grounding grids are the most important systems that increasing safety of power equipment in substations. The conductors of grounding grids usually connected together by fusion welding or bolts and nuts. But fusion welding make some problems for corrosion diagnosis of grounding grids and also pipelines while using ultrasonic technique. The main problem is incorrect results that obtained due to the interference of ultrasonic waves. This paper presented a new method to eliminating the effect of fusion welding points by placing the ultrasonic transducers in right locations. The influence of the soil is considered. Computer simulation results have shown the effect of this interference in accuracy of the result and effectiveness of the new method.