In 1984 a book entitled 'Les propri t s di lectriques de l'air et les tr s hautes tensions' was published. It represented a collection of research studies undertaken at EdF and other major world utilities over a significant period, and it has been widely used by manufacturers and users of high voltage equipment and systems, and by academic groups working in the area.

Undeniably, there have been a large number of developments in the high voltage field over the intervening years, but no such reference work has since been produced.

There have been a number of key advances in materials. Polymeric insulators are still under major trials for transmission voltages but have become widely used in overhead lines at distribution levels. Cable insulation has moved from paper systems to various polymer-based materials. SF ₆ has taken over as an efficient and reliable insulation medium in high-voltage switchgear, and gas-insulated substations are now frequently the preferred option for new substations especially in urban areas. All of these changes have not been direct substitutions; they have each required a reconsideration of equipment configuration, and new installation and operational techniques.

ZnO surge arresters are also widely used worldwide. Their excellent overvoltage protection characteristics have allowed design of modern compact systems to become more reliably achievable. The propagation of lightning and fault currents through earthing arrangements can now be modelled and predicted in much more reliable fashion. Much of this improvement in understanding has come from better use of numerical methods such as boundary elements, finite...