The role and the design method about guard rings, the gap between guard rings and field plates in VDMOS termination is discussed in the paper in detail.

The cause for one accident in Xichang power grid is analyzed,and it shows that misoperation of protective gas neutral point is the result of the unsuitable setting of neutral point protective gap of transformer.

This paper introduces the research on protective gap used in the live fine work of 500 kV transmission fine.

The influence of safety distance, protective gaps and working methods are analyzed and discussed.

Application of transformer gap protection in the power system with grounded neutral;

Discuss on operation and setting of gap protection of 110 kV primary transformer;

Based on three operation examples of the gap protection for 220 kV main transformers in Mawan General Power Plant,this paper analyzes the operating cause of the gap protection,and indicates that the transient overvoltage produced at the moment of single-phase grounding of system leads to the gap breakdown at the main transformer neutral.

The analysis on breakdown voltage of p n junction terminated with single floating field guard ring is presented.

In this paper,the surge protective gap based on hollow cathode effects was designed,the discharge curves were measured in air and nitrogen gas environment,and the critical pressure range was determined on condition that the voltage protective level Up was less than 4 kV.