Page 55 - Modern Control Systems

Section 1.9 Design Examples 29

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FIGURE 1.23 Smart grids are distribution networks that measure and control usage.

or off home and office appliances and devices. Smart home-energy devices enable the
homeowners to control their usage and respond to price changes at peak-use times.
The five key technologies required to implement a successful modern smart grid
include (i) integrated communications, (ii) sensing and measurements, (iii) advanced
components, (iv) advanced control methods, and (v) improved interfaces and deci-
sion support [87]. Two of the five key technologies fall under the general category of
control systems, namely (ii) sensing and measurements and (iii) advanced control
methods. It is evident that control systems will play a key role in realizing the mod-
ern smart grid. The potential impact of the smart grid on delivery of power is very
high. Currently, the total U.S. grid includes 16,000 power plants, about 3,300 utility
companies, and 300,000 miles of power lines. A smart grid will use sensors, con-
trollers, the Internet, and communication systems to improve the reliability and effi-
ciency of the grid. It is estimated that deployment of smart grids could reduce
emissions globally of C0 2 due to power systems by 14 percent by 2020 [91].
One of the elements of the smart grid are the distribution networks that mea-
sure and control usage. In a smart grid, the power generation depends on the market
situation (supply/demand and cost) and the power source available (wind, coal,
nuclear, geothernial, biomass, etc.). In fact, smart grid customers with solar panels or
wind turbines could sell their excess energy to the grid and get paid as microgenera-
tors [92]. In the subsequent chapters, we discuss various control problems associated
with pointing solar panels to the sun and with prescribing the pitch of the wind tur-
bine blades to manage the rotor speed thereby controlling the power output.