This paper introduces the basic principle of the transformer live detection and divides live detection technologies into two types of partial discharge or non-partial discharge. This paper describes several kinds of transformer live detection methods
including ultra-high-frequency partial discharge detection
ultrasonic partial discharge detection
high-frequency partial discharge detection
dissolved gas analysis of oil
infrared imagery
ultraviolet imagery
grounding current detection
relative capacitance and relative dielectric loss. At last the paper analyzes live detection methods application and existing problems.