6. Conclusion

The ongoing trend to reduce the overall dimensions of equipment is leading to a gradual increase in the service range of insulation, while maintaining high reliability and safeguarding the quality of the environment. Great care must therefore be taken in the choice of materials, particularly with regard to their short- and long-term rigidity.

Most high-voltage insulating materials use liquids selected to help eliminate partial discharges and facilitate heat dissipation, while preserving their insulating qualities: high resistivity, low dielectric losses, high rigidity. The latter depends on a multitude of factors and is not an intrinsic quality of the liquid itself. Of course, depending on the chemical formula, there are significant differences from one liquid to another, but the conditions of use also play a major role: form of applied voltage (alternating, continuous,...