Page 44 - From Smart Grid to Internet of Energy

Introduction to smart grid and internet of energy systems Chapter 1 33

The advanced substation gateway is also known as symmetric multi-
processing (SMP) gateway that is an improved computerized system merging
the acquired data from IEDs. The IEDs are also associated with circuit breakers
to perform several protection measurements, fault detection, monitoring and
control processes.
In this context, the distribution automation incorporates with line equip-
ment, ICT infrastructures, and data acquisition system along the distribution
network. Another major system is MDMS that is utilized to associate measure-
ment data acquired from several smart meters and diverse metering technolo-
gies [4, 23]. A wide variety of smart grid technologies are available to improve
efficiency and resiliency of transmission and distribution networks. In addition
to microgrid and substation automation technologies, other major smart grid
applications are distribution network automation and fault detection, isolation,
and recovery (FDIR) technologies. All this smart grid enabled transmission and
distribution automation technologies provide several benefits such as decreased
operational and maintenance costs, enhanced grid security, and economic
earnings.

1.2.4 Energy storage systems

The energy storage is an old application that has been applied since several
years. Moreover, ESSs are important systems for DR, electric vehicles, PV
energy systems, uninterrupted power supply (UPS), and remote energy plants.
The widespread usage of ESS is seen in pumped hydro plants and solar energy
plants. The storage applications are essential when operating intermittent RESs
and islanded and grid-connected operation modes shift regularly. The intermit-
tent structures of RESs are forced by weather changes and thus energy storage
provides a buffer in these conditions. The ESS selection is based on several
parameters such as each unit capacity, storage bank capacity, on-demand capac-
ity, self-discharge and deep discharge cycle, efficiency, life cycle of units,
reliability, and cost. The storage capacity means the available energy rate after
a full charge while self-discharge is the rate of the time required to reach to the
deep discharge capacity.
The fundamental ESS technologies are pumped hydro plants for long term
usage and advanced batteries, compressed air energy storage (CAES), super-
conducting magnetic storage systems, super capacitors and flywheels [24].It
should be noted that ESSs are mostly categorized according to rated power
capacity and time of discharge. Three use conditions of ESSs that are defined
depending to classification categories are power quality, power recovery, and
energy management. The power quality of an ESS is its capability to prevent
the voltage disturbances such as sags, flickers or supply interruptions during
supplying the load. The power demand from an ESS occurs in very short inter-
vals as seconds and can be rated from a few kW to MW rates. Therefore, ESSs
should be comprised by high power capacity flywheels, super capacitors or