Tuning of Converter Controllers in a VSC-HVDC Grid

Multi-terminal VSC-HVDC schemes (also called dc grids) are attractive alternatives to ac grids. Dc grids are potentially more robust and less affected by voltage, frequency or phase variations than would be the case with direct ac network connections. Designing controllers using analytical approaches, such as the root locus approach is difficult due to the complexity and nonlinearity of power systems that include VSC converters. Traditionally, simulation-based design was used where a human being conducts several runs to reach the desired set of design parameters. However, this can be a laborious and lengthy process. An alternative is to use optimization-enabled electromagnetic transient simulation (OE-EMTS), which automates the search process. However, the increasing number of terminals in…