Incorrect operation accident's analysis in overvoltage and differential protection of main transformer clearance

Modern power grid has already become one of the pillar industry of the national economy. The safety and steady operation of power grid is closely related to the development of all walks of life, national economy guarantee the fundamental interests of people. So it is significant to guarantee the safety of grid in production, operation, and the electric power supply. In this paper, connecting with a practical situation caused by dead ground, main transformer gap breakdown, broken CT neutral line, wrong actions of differential protection, and clearance overvoltage, some improvement measures and advices will be put out by comprehensively reviewing and detailed analyzing the reason and process of the accident to avoid the occurrence of such things.