The characteristics and application of vacuum switching devices

Vacuum switching devices arc enjoying rapidly increasing popularity in medium voltage applications. They have many attractive features resulting from the unique are extinction process in vacuum and these have spurred development in this direction. However, in early application the full implications of their exceptional rate of dielectric recovery were not appreciated and in some cases insulation damage has been caused in low impulse strength and high surge impedence load circuits. Much work has since been done to investigate transient voltages associated with vacuum switching devices, and it can confidently be said that these are now well understood. By judicious use of suppressor equipment when necessary, the advantages of these devices can be enjoyed without fear of damage to the insulation system of the switched equipment.