Page 127 - Decision Making Applications in Modern Power Systems

92 Decision Making Applications in Modern Power Systems

the overall use and values of existing productions and transmission capacity,
integrate greater levels of renewable energy sources (RESs), improve power
quality to correspond to new digital demands, become more reliable, resil-
ient, flexible, and sustainable. The key characteristics needed for these
changes are listed as follows [13]:
Intelligence (learning ability)
Two-way communication
Self-healing
Advanced metering infrastructure (AMI)

4.2.1 Challenges in smart grid power quality

Similar to every technology, smart grids bring some challenges to traditional
grids. Meanwhile, these also bring some new tools to improve the functional-
ities. The key challenges and tools that smart grids will bring are categorized
in the following subsections.

4.2.1.1 Power electronic devices
The recent progress in the field of power electronics has led to increasing
penetration of power electronic devices to the modern electrical grids; these
devices are like a double-edged sword, improving the electrical grid perfor-
mance in one side and bringing some new challenges such as injecting har-
monics to the electricity grid on the other. Nowadays, most of the RESs
need power electronic interfaces to connect to the main electricity grid, most
of the home appliances use power electronic converters, also power elec-
tronic converters are used in industrial loads and many other applications.
On the other hand, most of the power quality improvement (PQI) devices
that are developed to mitigate the power quality problems are power elec-
tronic based. Power electronic based PQI devices such as active power filter
(APF), dynamic voltage restorer (DVR), static synchronous compensator
(STATCOM), uninterruptible power supply (UPS) systems, smart impe-
dances, electrical springs (ESs), and multifunctional DGs (MFDGs) are of
this category [14].

4.2.1.2 Plug-in hybrid electrical vehicles integration
As is known, smart grid is green, meaning that it has the biggest potential to
deliver carbon saving. By growing tendency to the use of environment-
friendly vehicles, the future of the electricity grid will face a power quality
challenge. Integration of a huge amount of storage units that use rectifiers to
charge the batteries with different charge rates will greatly affect the power
quality of the electricity grid. Also, the peak demand will increase signifi-
cantly while injecting different orders of harmonic to the electrical grid. On
the other hand, this challenge could become an opportunity to improve the