Page 35 - From Smart Grid to Internet of Energy

24 From smart grid to internet of energy

operation conditions such as off-shore wind turbines, increasing temperature of
PV plants and so on. Therefore, the transmission system operators (TSOs) and
distributed system operators (DSOs) requires strict interconnection grid codes
to prevent unexpected operation and maintenance requirements. While the
improved power electronics devices play crucial role in development of DG;
the resource-based challenges make it difficult to improve the reliability, resil-
iency, flexibility, efficiency and scalability of DG integration to power grid.
Therefore, the researches and implementations are focused on improving highly
reliable and resilient DG plant integration to main grid. The resiliency of a DG
system requires some features such as anticipating the potential events, rapidly
recovering from detected events, and adapting to prevent future events. When a
sudden fault is detected in any section of the system, DG should rapidly respond
to the disturbances due to its control and operation management systems. The
response time, recovery duration and self-healing features are main indicators
of DG system resiliency [16].
Although DG is assumed as small-scale generation system located at the
consumer side to meet power demand of customer loads, large scale DG plants
are also integrated to transmission and distribution level of main grid. The inte-
gration levels and installed capacities of DG plants are rapidly increasing day by
day due to electricity power requirement all over the world. The decentralized
generation option provided by DG plants have brought several technical, eco-
nomic and environmental benefits. The technical advantages provided by DG
plants are seen in reliability improvement, voltage quality improvement, dec-
rements on the line losses, enhancements on security issues, and operational
benefits. The DG integration increases power system reliability by decreasing
peak power demand and capacity releases. On the other hand, it improves gen-
eration diversity enabling integration of a wide variety of power resources to the
main grid. The voltage quality of main grid is improved by reducing flickers and
providing better voltage regulation operations. Moreover, the active and reac-
tive power controls are improved and line losses are gradually reduced. The
resource diversity and increased integration ensure the security of critical loads
and increases power utility security by decreasing blackout risks. In addition to
this, CPS security is ensured by preventing vulnerabilities to intentional cyber
and physical attacks [16, 17].
The DG technologies are assumed as the initial applications that have
improved development of microgrid systems. DG plants have become essential
backup systems for traditional power system to prevent blackout and curtail-
ments due to their flexible integration features to the main grid. The DERs used
in a DG system are classified into two categories as RESs and conventional
resource-based plants. The conventional power plants are mostly comprised
by traditional power plants including synchronous generator such as gas tur-
bines, CHPs, steam turbines, micro turbines, and hydro plants. On the other
hand, RES based DG systems may include some synchronous generator-based
resources such as wind turbines, micro hydro plants, or geothermal sources