The influence of VSC - HVDC links on AC networks. Mathematical modeling and analysis

The current article is an analysis of the impact made by the implementation of a VSC – HVDC link within a Test Network, using SmartFlow/EUROSTAG softwares. Different operating scenarios will be analyzed from the point of view of the steady state regime: influence on power flows, N elements regime and contingency regime with N-1 elements, and also the impact over the power losses at the level of the analyzed AC network. To support this detailed analysis, the article also contains a synthesized presentation of the mathematical model that is the basis of modeling VSC-HVDC links in steady state and dynamic regimes.The conclusions of the article highlights the main advantages brought by the consideration of DC (Direct Current) links within modern AC networks, especially in the context of the Romanian National Electric Power System, where there is a tendency in renewable sources integration, which will lead to special requirements, in order to avoid system congestions, such as longer distances links, and additional support in the dynamic stability of the system.