The application of high voltage (HVDC) transmission for integrating large scale and/or off-shore wind generation systems with the electric grid is attractive in comparison to extra high voltage AC transmission systems due to a variety of reasons. A suitable control system is required for a VSC-HVDC system that provides good performance across a range of operating conditions. Two strategies are studied for their potential to enhance system robustness. The d-axis current control and DC power control are implemented in the outer-loop control at the receiving end of VSC-HVDC system. Small-signal analytical model is used to perform eigenvalues analysis and to design controllers. Both control techniques are investigated and the results are compared. An additional DC voltage droop control is added for both schemes. Its advantages were investigated. The droop gain and the cut off frequency of the DC voltage feedback filter are selected by analyzing the root locus of the analytical model to select the optimum values. It is established that d-axis current control with DC voltage droop control shows better performance practically for very weak AC system at both ends as well as with very long DC cable. The simulation results performed on PSCAD/EMTDC verify the feasibility of the control strategies effectively under different scenarios in order to confirm the obtained conclusions from analytical investigations.
No takes yet. Share an insight, caveat, or question.
Alsseid et al. (2017) studied this question.
Synapse has enriched 5 related papers. Consider them for comparative context: