Open to all Stanford students, faculty and staff.
Abstract: The increasing penetration of renewables has driven power systems to operate closer to their stability boundaries, increasing the risk of instability. We propose a multi-period optimal power flow approach that uses demand responsive loads to improve steady-state voltage stability, which is measured by the smallest singular value (SSV) of the power flow Jacobian matrix. In contrast to past work that employs load shedding to improve stability, our approach improves the SSV by decreasing and increasing individual loads while keeping the total loading constant to avoid fluctuation of the system frequency. Additionally, an energy payback period maintains the total energy consumption of each load at its nominal value. The objective function balances SSV improvements against generation costs in the energy payback period. We develop an iterative linear programming algorithm using singular value sensitivities to obtain an AC-feasible solution. The simulation results show that demand response actions can improve static voltage stability, in some cases more cost-effectively than generation actions. Compared with an iterative nonlinear programming algorithm from the literature, our approach is approximately 6 times faster in the IEEE 9-bus system, allowing us to demonstrate its performance on the IEEE 118-bus system.Bio: Johanna Mathieu is an Assistant Professor in the Department of Electrical Engineering and Computer Science at the University of Michigan, Ann Arbor. She received her PhD in mechanical engineering from the University of California, Berkeley in 2012 and was a postdoctoral researcher in the Power Systems Laboratory at ETH Zurich, Switzerland, before starting at UM in January 2014. Her research focuses on ways to reduce the environmental impact, cost, and inefficiency of electric power systems via new operational and control strategies. She is particularly interested in developing new methods to actively engage distributed flexible resources such as energy storage, electric loads, and distributed renewable resources in power system operation.