HVDC System Control for Damping of Subsynchronous Oscillations

A method for designing a supplemental subsynchronous damping control (SSDC) for an HVDC transmission system is described. The SSDC eliminates torsional instabilities caused by interaction between conventional HVDC controls and turbine-generator rotor torsional modes of vibration. Results of digital simulation used in the design process are compared with measurements made on an HVDC simulator. Results of both digital simulations and HVDC simulator tests which demonstrate SSDC performance are shown. This research and development effort was sponsored by EPRI under RP1425-1.