• Point-to-Point Link
• HVDC-VSC
• Islanded operation
• Frequency regulation

The high voltage direct current transmission systems of electricity, which use the voltage source technology (HVDC-VSC), are nowadays in continuous development. Thanks to their characteristics of flexibility of use and management, they easily find field for the integration with the traditional electric grid. These systems have been developed and improved considerably over the years, mainly because of the semiconductors IGBT performances grown either in power capability or in controllability. Therefore all these features have brought the VSC solution to be the dominant technology than the traditional current source systems (HVDC-CSC).
The present technical paper focuses on the model, the analysis and the management of a HVDC-VSC system in various grid configurations, starting from the case of point to point link, until the passive network management. The model is developed in MATLAB-Simulik ® environment.
The aim is to demonstrate that this technological solution is able to control independently one each other the fluxes of active and reactive power, to the nodes of connection with the AC grids. Besides, the study is based on the verification that this solution is also suitable to the management of an isolated grid, supplying its loads and predisposing the system to the grid reconnection. The analysis performed on the model are used to check the potential of VSC technology, in order to improve the management and the reliability of the electrical system where the HVDC-VSC link is installed.