  It is known that demand and supply power balancing is an essential method to
operate power delivery system and prevent blackouts caused by power shortage.
In this paper, we focus on the implementation of demand response strategy to
save power during peak hours by using Smart Grid. It is obviously impractical
with centralized power control network to realize the real-time control
performance, where a single central controller measures the huge metering data
and sends control command back to all customers. For that purpose, we propose a
new architecture of hierarchical distributed power control network which is
scalable regardless of the network size. The sub-controllers are introduced to
partition the large system into smaller distributed clusters where low-latency
local feedback power control loops are conducted to guarantee control
stability. Furthermore, sub-controllers are stacked up in an hierarchical
manner such that data are fed back layer-by-layer in the inbound while in the
outbound control responses are decentralized in each local sub-controller for
realizing the global objectives. Numerical simulations in a realistic scenario
of up to 5000 consumers show the effectiveness of the proposed scheme to
achieve a desired 10% peak power saving by using off-the-shelf wireless devices
with IEEE802.15.4g standard. In addition, a small scale power control system
for green building test-bed is implemented to demonstrate the potential use of
the proposed scheme for power saving in real life.
