Page 127 - From Smart Grid to Internet of Energy

Smart grid network architectures Chapter 3 111

highly scalable communication network among the utility and the user since
more user and application demand may be required in the future. It is considered
that time sensitivity is not a big issue for such type of applications. However,
field based applications are regarded to have time-sensitive characteristics.
Therefore, the utilities may have an option to dedicate separate communication
networks for every applications or they can use single shared communication
network for both groups. In addition, development cost can be minimized
through a shared FAN whereas a dedicated network provides real-time commu-
nication capability and further security.
Moreover, the FAN provides access opportunity to field devices through
smart devices such as laptops, notebooks, tablets and smart phones so as to
gather and investigate data for fault detection, troubleshooting and service main-
tenance. The FANs also accommodate a plenty number of devices and serve in
wide areas likewise to the NANs. The coverage of FANs and NANs may be
overlapped since several smart devices are connected to these networks for
implementations of many novel applications. For instance, the SMs should be
reachable by both of the FANs and NANs to provide that the distribution grid
is able to attain critical information from customer premises in real-time to per-
form effective volt/VAR control. Thus, numerous design rules and communica-
tion technologies are shared by the NANs and FANs. On the other hand, it is
adequate to merely address the NAN scheme since it can be taken into account
the representation of them.

3.5 Wide area networks (WANs)

A WAN is able to connect numerous NANs for collecting data from them and
then it forwards gathered data to utility private network that is a central control-
ler. The WAN makes possible long-haul communications between various
DAPs of power generation systems, distributed energy resources, transmission
and distribution systems, management systems and so on. The network scheme
also provides bidirectional communication infrastructures for enabling several
utility applications such as AMI, DR, DA, monitoring of power quality and
demand-side management. The coverage area of WAN is very wide that covers
approximately a few thousands of square miles, and its data rate is about 10–
100 Mbps. In addition, these networks are required to utilize high bandwidths
to ensure operation and control of these networks. The WAN aimed to establish
communication connections among the utility systems and SG applications.
Therefore, it covers two different network schemes that are called core network
and backhaul communication network. While a core network is associated with
metropolitan network of the utility and substations, the backhaul network is
associated with DAPs (NANs) of the network. These network schemes are
appropriate for data acquisition, status monitoring, fault detection, control
and management of power grid [23–26].