Automated replacement scheme of DC transformer bushing based on laser scanning profile: Design and experiment

•Replacing the bushing of the converter transformer in the valve hall.•Using short-arc profile data to solve the initial value of cylindrical fitting through the algorithm of circle and straight-line fitting.•Using 2D laser profiler to fit cylindrical parameters. The valve-side bushing is an important part of the ultra-high voltage (UHV) converter transformer. The bushing needs to be replaced at the converter station if the bushing is damaged. The bushing replacement of the existing project needs to be carried out by crane and manual operation. However, the replacement process takes a long time and the lifting accuracy is poor, which may cause damage to the bushing. A scheme based on a 2D laser profile scanner for automatic bushing replacement applied to direct-current (DC) converter transformer is proposed in this paper, which can replace any damaged bushing in the valve hall without removing other equipment. An initial value of the cylinder fitting algorithm based on the 2D laser profile is proposed in order to solve the position of the bushing, which fully considers the characteristics of the laser profile scanner, and uses the circle and straight-line fitting algorithm to solve the initial value. It is proved that the algorithm can improve the efficiency of cylinder fitting by comparing with the results of the mean value method. Industrial robots are used to implement the replacement scheme by using this algorithm, and the feasibility of the replacement scheme is verified.