On the design and placement of a supplementary damping controller in an embedded VSC-MTDC network

Abstract

This paper investigates the optimal placement and design of a Power Oscillation Damping (POD) controller within an embedded VSC-MTDC network. As VSC-MTDC networks are expected to play an eminent role in interconnecting AC grids, there is a growing need to optimize the placement and design of supplementary controllers in the MTDC converters, in order to maximize their benefit to the connected AC systems. Based on small signal stability analysis of the system, the location of damping controller within the MTDC network is selected according to the eigenvalue sensitivity of poorly damped oscillatory modes. On the other hand, the design of the damping controller is based on Modal Linear Quadratic Gaussian (MLQG) control that uses Wide Area Measurement Signals (WAMS). The results show the ability of the controller to enhance the damping in the system in case of disturbances, as well as to improve the small signal stability by boosting the damping of inter-area modes.