The mechanical characteristic test of operating mechanism can effectively diagnose the mechanical faults of high-voltage circuit breaker. The commonly used mechanical characteristic testing methods include such types as installation of linear displacement sensors and angle sensors. Both types of the sensors need to be firmly installed on the operating mechanism

and different circuit breakers may require different fixtures and sensors

resulting in weak universality. Moreover

fixed installation may increase the probability of mechanical failure. At present

the use of noncontact image recognition methods to test the mechanical stroke of high-voltage circuit breakers has received widespread attention from researchers. In this paper a non-contact measurement method is introduced. The diagonal sector markers with reflective function are pasted at the position of the movable pulling rof of operating mechanism of high-voltage circuit breaker. The markers are captured by a high-speed camera during the operation process of the high-voltage circuit breaker. The Shi-tomasi corner detection method is used to identify the center point coordinates of the sector markers in each image

calibrate the physical distance and pixel distance

thus obtaining a set of contact movement coordinate points and drawing the contact movement curve. The results show that compared with the circular marker image recognition method

this research method is simple

efficient with reliable result. Compared with traditional sensors

the mechanical travel curve obtained by this method is smoother and truly reflects the mechanical characteristics of the operating mechanism. This method has a good prospect for promoting the application of mechanical characteristic test in online monitoring outage maintenance of circuit breaker.