  This paper examines distribution systems with a high integration of
distributed energy resources (DERs) and addresses the design of local control
methods for real-time voltage regulation. Particularly, the paper focuses on
proportional control strategies where the active and reactive output-powers of
DERs are adjusted in response to (and proportionally to) local changes in
voltage levels. The design of the voltage-active power and voltage-reactive
power characteristics leverages suitable linear approximations of the AC
power-flow equations and is network-cognizant; that is, the coefficients of the
controllers embed information on the location of the DERs and forecasted
non-controllable loads/injections and, consequently, on the effect of DER power
adjustments on the overall voltage profile. A robust approach is pursued to
cope with uncertainty in the forecasted non-controllable loads/power
injections. Stability of the proposed local controllers is analytically
assessed and numerically corroborated.
