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The emergence of UHV AC/DC transmission systems and the installation of UHV equipment in heavily-polluted and high-altitude environments places challenges on the improvement of insulation systems. Part of the challenge can be met by the introduction of new dielectrics that offer superior properties. In particular the development of polymer-based systems that incorporate nano-sized fillers may allow for simpler, higher performance and lower cost & footprint systems. This paper offers an overview of developments being made in our laboratory that address problems associated with surface discharge and erosion. The paper presents some detail of the materials and processing developments along with some selected results and suggestions of candidate applications. [ABSTRACT FROM PUBLISHER]

In this paper, vacuum-cast epoxy-alumina nanodielectrics are reported with particular attention to the formulation and processing of the samples. Four grades of alumina nano-fillers with different particle size and surface treatments were compared. The samples were fully characterised in terms of their structure, mechanical, thermal and dielectric properties. The characterisations included: nano/micro-structure (optical and electron microscopy), mechanical properties (tensile, flexural and fracture properties), thermal properties (glass transition temperature, thermal expansion coefficient and thermal conductivity), and dielectric properties (dielectric constant, dielectric losses, DC volume conductivity and dielectric strength). Resistance to surface discharges was also evaluated. The results are discussed and compared to results commonly known for conventional epoxy composites. It is concluded that despite the initial benefits shown by nanotechnologies, there are still some challenges to overcome and more systematic research must be carried out in the choice of the nano-fillers, their size, their surface treatment and their dispersion. Materials selection, formulation and dispersion are the key steps to improve the consistency and reproducibility of nano-dielectrics. [ABSTRACT FROM PUBLISHER]