8. Perspectives and conclusions

It's always risky to try and predict the future of a technical field, because we can never rule out the possibility that an invention will profoundly change the current situation.

• The whole switchgear was modified by the discovery of the arc-extinguishing properties of SF ₆ , with the design of new devices such as SF ₆ circuit breakers and gas-insulated substations.

  The SF ₆ cut-off technique still has many years ahead of it, as there is no other gas known today with better cut-off and isolation qualities.

  Other gases or gas mixtures with good dielectric properties could be substituted for SF ₆ , but most of these...