Loop Shaping of a Wide-Area Damping Controller Using HVDC

Insufficiently damped inter-area oscillatory behavior in large power systems may be mitigated by the application of a feedback control system. Thorough investigation of the resonant features unique to the western North American power system suggests that the modulation of active power using high-voltage dc has great impact on retaining system stability when actuation is provided by the geographically expansive pacific dc intertie transmission line. The controller is limited in bandwidth by the influences of time delay, sensor and actuator dynamics, and specific plant characteristics. While proportional feedback of the scaled difference of two disparate bus frequencies has shown to be a valid method for controlling this particular system in previous work, the authors submit that a shaped loop transmission function provides performance and noise response improvement with guaranteed stability in saturation. Results of simulations using a high fidelity model of the system show the efficacy of the approach.