Damping of Electromechanical Oscillations by VSC-HVDC Active Power Modulation with Supplementary WAMS Based Modal LQG Controller

This paper presents a Multi Input Single Output (MISO) Modal Linear Quadratic Gaussian (MLQG) Power Oscillation Damping (POD) controller for Voltage Source Converter based HVDC systems. Applying this technique to a small (four machine) test network incorporating parallel HVDC/AC transmission has lead to improved damping of electromechanical modes compared with a traditional Power System Stabilizer (PSS) based controller structure. Furthermore, the MLQG controller has demonstrated greater robustness to varying operating conditions. The performance of the proposed control structure is assessed through small and large disturbance analysis.