  In this paper, we introduce Voltage Phasor Control (VPC), also known as
Phasor Based Control, as a novel way of implementing Optimal Power Flow (OPF).
Unlike conventional OPF, in which the power flow optimization broadcasts power
injections, the VPC power flow optimization broadcasts voltage phasor setpoints
to feedback controllers distributed throughout the network which respond to
disturbances in real time. In this paper, we demonstrate that VPC can actively
manage distributed energy resources to avoid voltage magnitude and line flow
constraint violations in power distribution networks. We provide sensitivities
and bounds that quantify how the distributed voltage phasor feedback control
reduces the effect of disturbances on the network voltages and line flows.
Using simulations, we compare the performance of VPC with the related but more
conventional Voltage Magnitude Control (VMC). The sensitivities, bounds, and
simulations provide implementation insights, which we highlight, for how
distribution network operators can use VPC and VMC to avoid constraint
violations.
