Laboratory Test and Feasibility Study of Two Countermeasures to Subsynchronous Resonance

This paper presents two countermeasures to subsynchronous resonance. One is a dynamic resistor which is controlled by thyristor switches based on shaft torsional oscillations. The other is a new dynamic compensator. Two types, called a dynamic current compensator and a dynamic voltage compensator, have been developed. Laboratory tests were conducted to investigate their damping forces against subsynchronous resonance. Results indicate that they can damp torsional interactions sufficiently; especially, a dynamic resistor has an excellent damping force. Analytical studies suggest that dynamic compensators can also stabilize induction generator effects. Stability analysis and transient simulations have good agreement with tested results.