An Online Feedback Optimization Approach to Voltage Regulation in Inverter-Based Power Distribution NetworksWe address the problem of controlling the reactive power setpoints of a set
of distributed energy resources (DERs) in a power distribution network so as to
mitigate the impact of variability in uncontrolled power injections associated
with, e.g., renewable-based generation. We formulate the control design problem
as a stochastic optimization problem, which we solve online using a modified
version of a projected stochastic gradient descent (PSGD) algorithm. The
proposed PSGD-based algorithm utilizes sensitivities of changes in bus voltage
magnitudes to changes in DER reactive power setpoints; such sensitivities are
learned online via a recursive least squares estimator (rLSE). To ensure proper
operation of the rLSE, the sequence of incremental changes in DER reactive
power setpoints needs to be persistently exciting, which is guaranteed by a
mechanism built into the controller. We analyze the stability of the
closed-loop system and showcase controller performance via numerical
simulations on the IEEE 123-bus distribution test feeder.
arxiv.org