Control of an HVdc Link Connecting a Wind Farm to the Grid for Fault Ride-Through Enhancement

Review of VSC HVDC connection for offshore wind power integration

“…If the applied blocking period is not long enough, over-currents are not totally avoided, leading to turbine trip-off. On the contrary, in the case of less severe faults, a longer blocking period than required can cause additional fluctuations at the connected power system [87]. For dealing with this issue, [87] proposes a variable blocking period, as function of the severity of each type of fault.…”

“…The suggested control strategy can avoid over-currents and the tripping of the turbines. Thus, it helps the system to quickly reach a steady state [87].…”

AC fault ride through of modular multilevel converter VSC-HVDC transmission systems

“…The reduction method can be subdivided into [30][31][32][33][34][35][36][37][38][39][40][41][42] The DC chopper based resistor method is the easiest to implement and is generally regarded as robust. This strategy leaves the wind and wave farms unaffected when there is an onshore fault [43].…”

Control of a Wind Farm Based on Synchronous Generators With a Central HVDC-VSC Converter

“…In both cases, HVDC systems require a power converter at the connection point of the wind farms, allowing a centralized control for the whole wind farm. Some offshore wind farms employ only this central power converter with squirrel cage induction generators [13] or synchronous generators [14], [15], while others combine a central power converter with individual converters and doubly fed induction generators [12] in each wind turbine.…”

“…However, the performance of this approach is not demonstrated for a wind farm with multiple wind turbines and a single power converter, when the different wind turbines are generating at different wind speeds. Other authors [13] proposed methods to dynamically search the maximum generation by changing frequency and observing power changes, but these methods present the drawback of possible operation at local maximums, that may generate much less power than an absolute maximum in certain cases. Therefore, the mentioned approaches do not guarantee maximum power generation for all wind speeds in the case of a wind farm connected to a single power converter.…”