In order to supply the high-quality electric power, several researches have been conducted. For the high-quality power, it is necessary to inspect the power lines and insulators before the lines or insulators are disconnected or damaged. However, it is not enough to inspect all the power lines by human inspectors. In previous study, a power line inspection robot was developed to investigate the power lines and insulators. According to replace the human operators by the robot, the inspection robot has several advantages: the improved working conditions, machine accuracy, and the prevention of accident. However, the robot has some defects in its heavyweight. In this study, a lightweight inspection robot has been developed using a RP and a vacuum casting. And, this study developed a fault detection monitoring program for the high voltage equipment using a microphone which detects the location of fault and the thermal imaging and CCD cameras which verifies the fault and stores the image, respectively.