What is solid insulated switchgear?

Solid insulated switchgear (SIS) is a form of switchgear that, as opposed to conventional gas or oil insulation, uses solid insulation materials between the live sections and the grounded metal body of the switchgear. The solid insulating materials are engineered to have superior dielectric strength and outstanding performance under settings of elevated temperature and humidity.

SIS has various benefits over conventional gas and oil insulated switchgear and is commonly utilized in medium voltage applications like power distribution systems. First off, in the event of internal arcing problems, the solid insulation materials used in SIS are safe for the environment and do not emit hazardous gasses into the atmosphere. Second, because SIS doesn't have big gas or oil tanks, it takes up less space than conventional switchgear. Last but not least, because SIS is unaffected by moisture or other impurities, it needs little care.

In retrofit applications, SIS can be built to replace existing gas or oil insulated switchgear with a variety of switchgear types, including circuit breakers and isolators.