Opportunities and barriers of high‐voltage direct current grids: a state of the art analysis

Abstract

Limiting the consequences of the climate change means that global CO2 emissions are to be reduced very rapidly. Taking into account that the expected economic growth of developing countries will inevitably be accompanied by a further growth in emissions in these countries, there is a strong necessity that the energy systems in the industrialized world be transformed into emission‐free ones. This level of reduction requires, for example, that the European Union achieves a ‘nearly zero‐carbon power supply’, involving replacing of fossil fuels in most or all buildings and much of the transport sector by nearly zero‐carbon electricity. It is also clear that the current political framework is, especially in Europe, propitiating the large‐scale implementation of renewable energy sources. In order to make this large implementation economically feasible, it is essential that the potential of these sources is maximized, placing them at sites providing the highest possible output. These sites are often located far away from consumption centers, making compulsory the transmission of large amounts of energy from generation to demand. In the global scenario, the necessary capacity of the power infrastructure for doing such exceeds by far the existing infrastructure and therefore new transmission capacity is necessary. Taking into account that large amounts of Renewable Energy Sources (RES) are to be integrated in the current power system and that most of the generation will take place at remote locations requiring new transmission assets, this article answers the question of whether a supergrid is necessary to enable this transformation. This article is categorized under: Energy Infrastructure > Systems and Infrastructure Energy Infrastructure > Climate and Environment

Review of energy system flexibility measures to enable high levels of variable renewable electricity

“…Supergrid is a strong network of transmission lines typically incorporating at high-voltage direct current (HVDC) technology [319][320][321][322][323][324]. Such a grid is capable for connecting remote RE power sites with demand.…”

“…HVDC transmission lines have already been realized in subsea cables, but not yet in intercontinental context where high voltage AC would still dominate. Main challenges with HVDC are related to installation, technical standards, interaction with AC grid, and operational principles [319,320,324].…”

Review of DC fault protection for HVDC grids

“…For power transmission over long distance using cables, for example, connection of large offshore wind farms, high‐voltage DC (HVDC) has significant advantages compared to conventional AC technology due to the large reactive power consumption in AC cables (Coll‐Mayor & Schmid, ). HVDC also allows power transmission between unsynchronized AC systems.…”

“…In addition, HVDC connections help increase system stability by preventing fault propagation and stabilize the predominant AC grid without increasing fault current level. HVDC also offers better active power controllability and can provide ancillary services for the connected AC grid, for example, power flow redistribution, power swing damping, frequency stabilization, and so forth (Coll‐Mayor & Schmid, ; Hasanuzzaman, Zubir, Ilham, & Seng Che, ; Zhang, Ravishankar, Fletcher, Li, & Han, ). A typical HVDC terminal contains the converter station, transformer, AC filters (if used) and associated control and protection equipment.…”