Abstract The transformer is an important equipment in a factory, providing reliable power for the factory, which is guaranteed the normal production of the factory. The lightning arrester is one of the important protection equipment to ensure the safe operation of power system. This paper introduces a 110kV transformer tripping for differential protection and the heavy gas movement, demolition lightning arrester on the transformer, found that the cone of arrester was cracked, and analyzed the causes. Finally put forward some reasonable suggestions of such lightning arrester installed on the transformer.