Novel HVDC spacers by adaptively controlling surface charges – part iii: industrialization prospects

The design of spacers for operation under DC stress is a challenging part for gas-insulated substations (GIS) and gas-insulated transmission lines (GIL). This series of papers has proposed a novel way to develop a spacer for operation under high-voltage direct-current (HVDC) conditions. In this part, a model spacer based on adaptively controlling surface charges is briefly introduced and is verified using routine tests, including electric field strength simulations, X-ray imaging, mechanical simulation and mechanical testing. In addition, the thermal expansion coefficient and thermal conductivity of the spacer are also measured to investigate its operational stability under various thermodynamic conditions. The results show that the geometrical improvements and SiC doping are available to reduce both the normal electric field strength around the central electrode and the tangential electric field strength around the enclosure. The mechanical properties of the concave side of the spacer are slightly lower than those of the regular spacer, while the mechanical properties of the convex side demonstrate the major improvements during both simulations and water pressure-based destructive testing. It is hoped that this work will provide a new approach for the design of spacers for use in HVDC GIS or GIL.