Page 117 - From Smart Grid to Internet of Energy

Smart grid network architectures Chapter 3 101

and manage smart home appliances (e.g., refrigerators, air conditioners, kitchen
stoves, heaters, dishwashers, washing machines, dryers, chargers for electric car
and so on) for making perfect the power supplies and energy consumptions. The
best part of a HAN is that it can share energy consumption rates with in-home
monitors, and it is able to offer functionality to turn off cycling heaters or air
conditioners during peak load conditions. Besides that, the HAN also provides
a card-activated prepayment scheme and managing the charging and dischar-
ging processes of plug-in electric vehicles (PEVs).
HEMS is a very important component of a HAN which not only authorizes
users to follow how much power is being consumed by their home appliances
at any specific point of time but also in a wide time frame. The HAN comprises
of the SM, actuators, smart sensors, smart appliances, intelligent electronic
devices (IEDs) and home gateway (HGW). The HEMS interconnects with a
SM mounted in user site to expedite SG applications regarding DR, time of
use (TOU)-based energy management and so on, and undertakes a communi-
cation gateway (GW) role to transmit information including price of real-time
energy, energy consumption, and control command among the HAN and the
utility. The HEMS also authorizes the users for managing their home appliances
in order to reduce their energy consumption and electricity bill. Generally, a star
topology is used in HAN scheme for both wired technologies (e.g., Ethernet and
power line communication (PLC)) and wireless technologies (e.g., ZigBee and
Wi-Fi) [12]. Normally, HANs allow approximately 10–100 kilobits per second
2
(Kbps) data rates and cover areas of up to 200 m . On the other hand, all home
appliances can be connected together using wireless connections (generally
using the unlicensed 2.4 GHz frequency) by deploying smart metering concept.
Whole home appliances can be controlled by SMs and they provide a complete
data about the power usage of every appliance [13]. The comparison of HAN
communication based on wired and wireless technologies is shown in Table 3.1.
There are certain applications which are very important for the HANs like
home automation, building automation, and industrial automation. Authorizing
and control are two essential and inevitable functionalities offered by a HAN
scheme. Authorizing is responsible to detect and manage different piece of
equipment that are forming a self-organizing network whereas control function
of a HAN tries to provide promising interoperability among the different com-
munication sections of the SG.
The SG (or utility center) and the end user relationship are of utmost impor-
tance. Therefore, an interface between the utility and the consumer called
energy service interface (ESI) is used which behaves as secure bidirectional
communication interface between them. Various kinds of interfaces may be
supported by the ESI for ensuring secure bidirectional communications. The
main purpose of utility secure interactive interface is to present secure two-
way communication whereas utility public broadcast interface is being utilized
in order to provide price signaling and one-way reception of event at user
devices. For exchange of metering information, the ESI may be interconnected