Measurements of high voltage DC fields in air

The global demand for electric power continues to increase in most countries but in particular in non-OECD (Organisation for Economic Cooperation and Development) countries [1]. Often the generation is located far from the consumers, and this requires transmission of electric power over long distances. For various reasons, high voltage direct current (HVDC) is often the preferred technology for these links [2]. To keep losses at a minimum, the voltage must be as high as possible, and this has stimulated the development of ultra-high voltage DC transmission. Over the last decade, 800 kV has been established as a new standard level for long transmission links [3].