The most primitive surge protector, the claw-shaped gap, appeared in the late 19th century and was used for overhead transmission lines to prevent lightning strikes from damaging equipment insulation and causing power outages. In the 1920s, aluminum surge protectors, oxide film surge protectors and pill surge protectors appeared. Tubular surge protectors appeared in the 1930s. Silicon carbide lightning protectors appeared in the 1950s. Metal oxide surge protectors appeared again in the 1970s. Modern high-voltage surge protectors are used not only to limit overvoltages caused by lightning in power systems, but also to limit overvoltages caused by system operations. Since 1992, industrial control standard 35mm rail snap-on pluggable SPD lightning protection modules represented by Germany and France began to be introduced to China on a large scale. Later, integrated box-type power supply lightning protection combinations represented by the United States and Britain Also entered China.