Page 142 - From Smart Grid to Internet of Energy

126 From smart grid to internet of energy

between HDR and LDR NB PLC technologies. The standards, technical spec-
ifications and application areas of LDR and HDR NB PLC systems are listed in
Table 4.1 [35].

4.2.3 Broadband PLC
The success of the NB PLC systems encouraged development of the BB PLC
systems, and primary application studies have been performed for internet
access and HAN applications. The first application that aimed to enable Internet
access to residential customers over power lines were developed by Nortel and
Norweb Communications in Europe. The developed technology has been tested
in a network composed of homes and schools, and >1 Mbps data rates have
been achieved thanks to performed experiments [17, 36]. Unfortunately, the
project has been terminated in 1999 due to cost and EMC issues. Other projects
conducted by Siemens and Ascom experienced similar situations. The Open
PLC European Research Alliance (OPERA) project that was funded by the
European Commission provided significant improvements in the field of the
BB PLC.
After the first unsuccessful period of BB PLC, home applications and indus-
trial communication applications of BB PLC systems have become more pop-
ular for industrial areas in the early 2000s. The HomePlug, UPA, HD-PLC, and
The HomeGrid Forum have played important roles for BB PLC systems. In
2005, HomePlug AV was proposed for indoor environments in order to enable
multi stream networking with high quality feature. Depending on its advanced
PHY and MAC layer characteristic, this standard is capable to achieve 200 Mbps
data rates over AC power lines in-home networks. Therefore, it provides high
quality broadband services containing audio, video and data over existing
power lines of home areas. Furthermore, HomePlug AV can support High-
Definition TV (HDTV) and Voice over Internet Protocol (VoIP) applications
owing to ensuring high data rates. The most popular commercial devices are
compatible with HomePlug AV and HD-PLC standard. The MAC layer of these
devices exploits time-division multiple access (TDMA) method and CSMA/CA
protocol. In addition, it is important to note that the PHY layer of the IEEE
P1901 standard has been created based on the HomePlug AV and HD-PLC stan-
dard. In 2010, HomePlug Green PHY that has been released as a special type of
HomePlug AV standard presents low cost and low power consumption features
for potential SG applications. Specifications of popular BB PLC standards and
technologies are listed in Table 4.2 [35].

4.3 Characteristics of power lines
Power lines were exploited to carry electrical power in every place of the world
until developments in signal processing and communication systems demon-
strated that power lines can not only employed to deliver the electrical power,