(Georgia Institute of Technology, 2016-07)
Ramachandran, Thiagarajan; Nazari, Masoud H.; Grijalva, Santiago; Egerstedt, Magnus B.
This paper proposes a general framework for determining
the effect of communication delays on the convergence
of certain distributed frequency regulation (DFR) protocols for
prosumer-based energy systems, where prosumers are serving
as balancing areas. DFR relies on iterative and distributed
optimization algorithms to obtain an optimal feedback law
for frequency regulation. But, it is, in general, hard to know
beforehand how many iterations suffices to ensure stability. This
paper develops a framework to determine a lower bound on the
number of iterations required for two distributed optimization
protocols. This allows prosumers to determine whether they can
compute stabilizing control strategies within an acceptable time
frame by taking communication delays into account. The efficacy
of the method is demonstrated on two realistic power systems
(Georgia Institute of Technology, 2012-09)
Ramachandran, Thiagarajan; Costello, Zak; Kingston, Peter; Grijalva, Santiago; Egerstedt, Magnus B.
Due to requirements of renewable and distributed energy integration,sustainability and energy security, the existing power grid is undergoing radical changes.The lines between producers and consumers are becoming blurred. In this paper, we provide a constrained formulation of the power allocation problem, which is emerging in such producer-consumer hybrid environments, and obtain decentralized protocols for its solution. We show that the information required by the individual prosumers to solve the problem varies depending on the choice of constraints in the optimization problem. As a consequence of this, we demonstrate that there exist fundamental trade-o s between the information required and the convergence rates associated with the power allocation problem.