This paper proposes a hierarchical control architecture
for engaging demand into providing primary frequency
response services. The proposed architecture relies on the use of
information about accumulated energy for the aggregation of demand
capabilities and dissagregation of demand responsibilities.
Since the accumulated energy has a distinct additive property, the
aggregation/disaggregation of demand becomes straightforward.
Additional unique features of the proposed architecture are
that it: i) includes the information of inflexible load in the
aggregated demand, ii) allows for intuitive cooperation between
load aggregators. Conditions for stability under cooperating load
aggregators are derived. Finally, simulations are carried out on
the IEEE 39-bus system to illustrate the proposed concepts of
aggregation, disaggregation and cooperation.NSF initiative, Award no. EFRI-144130
