5. Conclusion

Among the many applications for glass in electrical engineering, those where the electrical voltage is directly insulated by the glass are mainly in the power transmission sector. Today, two families of insulators coexist in this field. On the one hand, molded insulators, today mainly made of tempered glass, make up the bulk of the application. The glass used is of the soda-lime-silica type, with some nuances in chemical composition for DC applications. Thermal tempering enables very high mechanical loads to be applied. Glass is also used in composite materials, where fibers are used for mechanical reinforcement of insulating materials. A number of operating incidents have been reported in recent years, in particular as a result of chemical degradation of the fibers by acids generated by nearby electric fields. New, largely unexplained failure modes are appearing on composite insulators...