Gases as Insulating Medium
Gases used as insulation must satisfy the following basic requirements :
- Gas must be chemically inert and should not react with dielectrics, in combination with which it is used, and with other materials used in the construction of the apparatus.
- During the ionization of the gas, which to a certain degree is always possible in high voltages apparatus, chemically active substances should, not be emitted.
- Gas must possess a low temperature of liquefaction, since it will not be possible to use it at increased pressures (With increase of pressure;temperature at which gas changes into liquid increases).
- Gas must possess as high as possible electric strength and high heat conductivity. The last one is especially important in those cases when the gas simultaneously serves as an insulating as well as cooling medium.
- The cost of gas must be sufficiently low, so that its use is economically justified.