  The Model Predictive Control (MPC) approach is used in this paper to control
the voltage profiles in MV networks with distributed generation. The proposed
algorithm lies at the intermediate level of a three-layer hierarchical
structure. At the upper level a static Optimal Power Flow (OPF) manager
computes the required voltage profiles to be transmitted to the MPC level,
while at the lower level local Automatic Voltage Regulators (AVR), one for each
Distributed Generator (DG), track the reactive power reference values computed
by MPC. The control algorithm is based on an impulse response model of the
system, easily obtained by means of a detailed simulator of the network, and
allows to cope with constraints on the voltage profiles and/or on the reactive
power flows along the network. If these constraints cannot be satisfied by
acting on the available DGs, the algorithm acts on the On-Load Tap Changing
(OLTC) transformer. A radial rural network with two feeders, eight DGs, and
thirty-one loads is used as case study. The model of the network is implemented
in DIgSILENT PowerFactory, while the control algorithm runs in Matlab. A number
of simulation results is reported to witness the main characteristics and
limitations of the proposed approach.
