Technical and compatibility issues in the design of HVDC sea electrodes

Abstract

The HVDC (High Voltage Direct Current) transmission system, although in use since about half a century, is gaining new popularity in recent years, as it can allow to transmit very large amounts of power over long distance at reasonable costs. Many plants are being commissioned and many others are in the design phase, both for mainland and submarine links. Ground/sea electrodes are normally used in such applications, either operated on a full time basis, or during partial failures of one pole of bipolar plants. Due to the adverse effects that stray currents dispersed by such electrodes may have in terms of corrosion to nearby structures, and to the growing concern for environmental issues, the design of sea electrode has to be defined with increasing attention. This paper deals with the technologies and with the design criteria that can be adopted to develop satisfactory sea electrodes.

Ground/sea return with electrode systems for HVDC transmission

“…A disadvantage of the ring pattern is that it requires a large area of land -with unused space in the center -which may be difficult to find. The preliminary sizing of a ring electrode expresses its resistance to remote earth as follows [18]: ) where D is the diameter of ring center line, 4 = √ ℎ where d is the diameter of conductor and h is the burial depth from the surface of the earth to the center point of the electrode. When appropriate values are entered in (2), D is found via an iterative process by equating the value of Re after (7) to the desired resistance to remote earth.…”

Analysis on structural parameters and electrical performance of dc deep well grounding electrode

“…In order to minimise the impacts above, it is advised that the HVDC electrode has a larger scale, a smaller ground resistance and step voltage etc. and has stricter requirements on the electrode material and site selection [5, 6].…”

Experimental Study on Gas Evolution Characteristics of DC Deep Well Grounding Electrodes

“…Economic and social issues due to land expropriation policy and a shortage of land resources limit site selection [5]. Thus, it is necessary to seek an economic and applicable HVDC electrode scheme [6]- [8].…”