Remote offshore wind power plants are expected to be connected via HVDC systems to the main grids. The extension of single point-to-point HVDC systems into meshed HVDC grids is discussed actively. This leads the integration of DC technology into the collection grid of the wind farm to gain interest and relevance. Using DC technology in the collection grid demands the wind turbine systems to hav...

To transfer large amount of direct current power having high amplitude voltage over long distance, high voltage direct current (HVDC) transmission system is used. This system was introduced 60 year ago and now it is widely used all over the world. Some examples of HVDC systems are following; Voltage-SourcedConverter (VSC), current commutated converter (CCC) and line commutated converter (LCC) d...

Controlled islanding has been widely discussed in the literature as a novel concept for the power system protection. However, the islanding can result in unbalanced islands where the power mismatch will often cause an instability that can lead either to a subsequent load shedding or generator tripping within the islands. Controlled VSC-HVDC links can mitigate the negative consequences of the co...

the ultimate goal of power system operation and planning is to increase power system reliability which enforces interconnected operation of power system. as a result of power system interconnection, the inter-area oscillation under different disturbances may cause power system partial or total blackout. dc-segmentation of interconnected power systems is a solution in which the topology of the n...

For AC railway power supply systems with a different frequency than the public grid, high-voltage AC (HVAC) transmission lines are common, connected to the catenary by transformers. This paper suggests an alternative design based on an HVDC (High Voltage DC) feeder, which is connected to the catenary by converters. Such an HVDC line would also be appropriate for DC-fed railways and AC-fed railw...

The voltage source converter-high voltage direct current (VSC-HVDC) transmission is the ideal integration technology for grid-connected wind farms. A passivity-based control (PBC) method for VSC-HVDC when the wind farm voltage is unbalanced is proposed in this paper. The mathematical model of a VSC with unbalanced voltage is established. The PBC theory including dissipation inequality and syste...

Priority access of renewable resources such as offshore wind recommended by European energy directives, new market models and trading the electric energy among countries lead to new requirements on the operation and expansion of transmission grids. Since AC grid expansions are limited by legislative issues and long distance transmission capacity, there is a considerable attention drawn to appli...

High-voltage direct current (HVDC) lines with line-commutated converter (LCC) are being increasingly employed to transmit bulk wind power over long distance. However, this may cause the sub-synchronous torsional interaction (SSTI) between the wind farms and the LCC-HVDC system. The SSTI characteristics of wind farms with fixed-speed induction generator (FSIG) wind turbines connected to LCC-HVDC...