Environmental and geographical aspects in HVDC electrode design

An essential element in HVDC electrode design is to minimize all environmental stresses in order to meet and verify conformance to the laws and regulations associated with the concessions granted by the authorities. The environmental disturbance caused in anode or cathode operation is more or less entirely dependent on the materials used, the geographical location and the electrode size. The electrode materials and the related electrochemical process in the surrounding medium are discussed in the paper in order to shed further light on the chemical properties of different materials in an electrolyte process. The geographical location of an electrode is described, taking into account new aspects such as the impact of the Earth's magnetic field and the interaction with existing HVDC electrodes. The experiences described in this paper are based on the design, tests and operation of the electrodes in the Baltic Cable HVDC link and other Scandinavian HVDC links.