This paper describes the development of a multimachine, multi-device dynamic stability program based on the complex torque coefficient technique which has received limited attention in the literature. Unlike the conventional techniques, this approach aims to give a clearer explanation of the complex mechanisms that are responsible for synchronous machine instability for the full range of dynamic stability phenomena including self-excitation, subsynchronous resonance (SSR), subsynchronous torsional interaction (SSTI), and intermachine interactions.