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Center for Nonlinear Studies |
Electrical transmission grids rely on generator inertia, frequency droop control, and automatic voltage regulation (AVR) to maintain transient stability following power system contingencies such as faults. Generator inertia and frequency droop modify real power and primarily act in a “global'' sense, i.e. they respond to the global transient imbalance of generation and load. Under high loading or extended fault durations, this global response may be insufficient to maintain transient stability. We propose additional automatic controls that create a local real power response to a contingency. Specifically, for every generator, we add an input to its turbine governor proportional to the deviation of the power flows on the generator's adjacent transmission lines from a nominal steady state. Using dynamical simulation of the post-contingency dynamics, we optimize over the \emph{gains} of these power flow feedbacks to improve the transient stability of the network. The optimization step enables these controls to be adaptive to changing power system conditions. We demonstrate the effectiveness of this approach by incrementally loading a test network while optimizing the power flow feedback gains to delay the onset of transient instability for a given critical clearing time applied to all contingencies.
Host: Misha Chertkov