On the Equality of Modal Damping Power and the Average Rate of Transient Energy Dissipation in a Multimachine Power System

This letter establishes a relationship between the concepts of damping torque and the dissipation of transient energy in a multimachine power system with constant power loads. To that end, we present a mathematical proof showing that, for a poorly-damped mode, the total damping power stemming from the interaction of electromagnetic torques and rotor speeds is approximately equal to the average rate of transient energy dissipation in the system corresponding to the modal oscillation. This is verified with numerical studies on the IEEE 2-area 4-machine and 5-area 16-machine test systems.