 |
Center for Nonlinear Studies |
Power systems are critical infrastructures that support indispensable services such as hospitals, transportation systems, and telecommunications. One of the many requirements that power systems need to satisfy is to ensure that voltages and currents in the power grid are sinusoidal with a synchronous frequency of 50 or 60Hz. The preservation of synchronization of generator frequencies, also known as the transient stability problem, is one of the most important problems in power systems, since failure to achieve this objective would cause serious damage in power system components that were developed under the assumption of sinusoidal voltages and currents with constant frequency. Traditional models that are used to study the transient stability problem has an implicit assumption: the waveforms in the model are sinusoidal signals with a frequency that is very close to the synchronous frequency. This assumption is known to be violated in real life scenarios. The final stage of the August 14, 2003 blackout is an example of such violations. This makes us question the validity of the existing tools and methods, based on classical assumptions and models, to analyze transient stability. In this work, we eliminate hard-to-justify assumptions such as constant frequency by replacing traditional models with energy-based models derived from first principles. Using the energy-based model, we derive an easy-to-check condition that guarantees the transient stability of power systems. The derived transient stability condition is compositional, since we infer the transient stability of the interconnected system by checking a condition for each individual generator.
Host: Misha Chertkov