A critical evaluation of the application of HVDC supplementary control for system stability improvement

Bulk power transfer requirements over long distances within a country or between neighboring countries as well as rapid increase in the number of offshore wind farms, have increased the application of high voltage DC links. Apart from the controllable power flow function of HVDC systems, advanced controllers can be employed to extend their functionality for dynamic and transient stability improvement of the underlying AC systems. This paper compares and critically evaluates HVDC supplementary controller strategies for improving AC system stability. A Preliminary explanation of the controller design process for each controller type as well as a brief comparison on their application to damp the inter-area oscillations have been presented in this paper.