The shielding system of the vacuum interrupter is mainly composed of a shielding cylinder, a shield and other parts.

The main functions of the shielding system are:

1. Prevent the contact from generating a large amount of metal vapor and droplet splash during the arcing process, pollute the inner wall of the insulating casing, and avoid causing the insulation strength of the vacuum interrupter casing to decrease or flashover.

2. Improving the electric field distribution inside the vacuum interrupter is beneficial to the miniaturization of the vacuum interrupter insulation casing, especially for the miniaturization of the high voltage vacuum interrupter.

3. Absorb a portion of the arc energy and condense the arc product. In particular, when the vacuum interrupter is turned off, the thermal energy generated by the arc is mostly absorbed by the shielding system, which is beneficial to improve the dielectric recovery strength between the contacts. The greater the amount of arc-absorbing product that the shielding system absorbs, the greater the energy it absorbs, which plays a good role in increasing the breaking capacity of the vacuum interrupter.

The contact is the part that generates the arc and extinguishes the arc, and the material and structure requirements are relatively high. The contact structure has a great influence on the breaking ability of the isolation chamber. The arc-extinguishing effect produced by different structural contacts is different. In the early stage, simple cylindrical contacts were used. Although the structure is simple, the breaking capacity can not meet the requirements of the circuit breaker, and only the current below 10kA can be broken, and only Vacuum load switches, high-pressure vacuum contactors, etc. are only used with vacuum switch tubes. There are three kinds of spiral-shaped structural contacts, cup-shaped structural contacts with inclined grooves and cup-shaped structural contact with longitudinal magnetic field, among which the vertical magnetic field cup-shaped structural contacts are mainly used.