The work describes high-voltage transmission using direct current (DC). By comparing different ways of transmission, HVDC and HVAC, findings on reasonable implementation of the DC system transmitting electric power in Slovenia and worldwide are presented.
The work is divided into four parts. The first part presents the historical development of HVDC beginning with Thury's transmission system. The latter evolved throughout a breakthrough towards the invention of semiconductor HVDC as we know it today.
The second part accurately describes the structure of HVDC systems and different types of connections, from monopolar, bipolar to the »back-to-back« version. Furthermore, individual components that are necessary for an HVDC system to function are presented.
The third and the most extensive part analyzes differences between HVAC, HVDC LCC and HVDC VSC systems. The obtained results allow prediction of energy transmission distances where a certain system investment is feasible compared to another. Aspects of availability and required space are also included, minding integration into environment.
The last part presents details about the HVDC VSC technology. Favourable characteristics offer a possibility for direct transmission in the future. Despite greater losses in comparison to LCC technology, HVDC VSC offers functioning in all four P/Q quadrants and is, therefore, opening up new possibilities for a simpler integration with existing HVAC systems. The possibility of integration makes spreading these connections across Europe possible. The findings are based on a study showing that the adoption of an HVDC system in Slovenia may strengthen the interconnection with Italy as well.
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