POWER February 2021 - 23

CONNECTED PLANT
pected to rise steadily over the next few
decades, often to meet national targets.
In Japan, for example, the goal is for 22%
to 24% of the power supply to come from
renewable energy by 2030. To meet these
and similar goals worldwide, new automation
solutions will be required.
IoT-Based Energy Management
Systems Address Issues
Each renewable site can benefit by measurement,
control, real-time monitoring,
and Internet of Things (IoT)-based communication
capabilities. Measurement
is performed by a variety of instruments
and sensors to determine electric current
and voltage, flow rates, pressures,
temperatures, levels, vibration readings,
and other parameters. Technology to
capture, monitor, and communicate this
data is required at each site.
Each site also requires some type
of local real-time control. As previously
mentioned, automation system platforms
and communication capabilities
are not consistent from one type of renewable
source to the next, requiring
integration among automation systems.
A relatively new type of automation component,
typically referred to as an edge
controller (Figure 1), is well-suited to
provide this required functionality as one
of the core components of an IoT-based
energy management system (EMS).
This edge control capability can be deployed
for new and existing asset implementations.
These controllers integrate
with OEM automation technologies, effectively
extending the capability of automation
and SCADA systems that may
not have been originally designed or envisioned
to perform required functions.
Typically, existing automation systems
will support various means of
communications. Popular
serial
digital
protocols
such as Modbus RTU (remote terminal
unit) allow a host of variables to be
communicated between existing automation
systems and an edge controller.
More advanced protocols are supported
by many automation systems and are
usually Ethernet-based, providing higher
bandwidth and greater speeds as compared
to serial communications.
Whether acting as the main automation
system or connecting to existing
automation systems, an edge controller
will provide the functionality required to
monitor and control the local equipment,
and to communicate with an ROC. As
with all internet-based communications,
cybersecurity concerns must be
addressed, a detailed topic that will not
February 2021 | POWER
2. This system architecture depicts deployment of an Internet of Things (IoT)-based management
system for a wind farm in Japan. Courtesy: Yokogawa
be covered in this article other than to
say there are national guidelines in most
countries and regions for electrical infrastructure
digital communications.
The ROC usually hosts a SCADA system,
which connects to the edge controllers
installed at each remote site. The
SCADA system also integrates information
regarding power demands from the grid,
the power output from various generation
resources, and the status of energy
storage assets. Using information from
all these sources, the SCADA system
provides the required coordination among
generation, demand, and power storage.
Edge controllers and a SCADA system
combine to provide an IoT-based EMS
to perform energy planning and performance
management, and they can also
add prediction optimization using big data
and analysis algorithms. This functionality
and data gathering are required to support
the operations and management at both
the facility and the business level. The following
example shows how an EMS is
used to coordinate power produced by a
large wind firm with grid demand.
Wind Farm Use Case
Many wind farms have been constructed
in Japan since 2000, and Yokogawa has
been providing EMS solutions to these
wind farms commencing in 2015 and
continuing to the present. For example,
a large wind farm in Japan uses an EMS
based on Yokogawa's edge controllers
and their SCADA solution. Yokogawa
participated in the project as the system
provider from the beginning of construction
through to final commissioning.
Yokogawa supplied the following
equipment and services:
■ e-RT3 real-time-OS-based or STARDOM
controllers for monitoring and
operation of substations and a switchyard,
enabling remote operation and
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monitoring from the ROC. These
controllers are used to monitor equipment
status, process value readings,
and alarms-and they communicate
with the power utility, turbine controllers,
and control switches.
■ FAST/TOOLS SCADA for supervisory
facility monitoring and control. The
SCADA system communicates with
the substations, switchyard, and wind
turbines at intervals of one second
or less, and it displays readings and
status. In addition to real-time monitoring,
the SCADA system facilitates
administrative tasks such as daily and
monthly reporting.
■ System components consist of administrative
servers, PC-based monitoring
systems, and peripherals (Figure 2).
■ Network and cybersecurity architecture
designed to support the local
wind farm network and integration to
the ROC, as well as secure connectivity
to external third parties.
■ All associated engineering and on-site
services to implement, test, and deliver
the operational solution.
The entire system has been operating
reliably since its installation, supplying
clean power to the grid and helping Japan
meets its renewable energy goals.
As renewable generation technologies
continue to account for an increasing proportion
of the global energy mix, the intermittent
nature of these assets will present
challenges for integration with the grid.
However, these issues can be addressed
by deploying the latest automation and
IoT-based technologies that offer extensive
functionality and advanced optimization capabilities,
resulting in lower levelized cost
of energy and more reliable operations. ■
-Tatsuya Yamaguchi is a manager with
Yokogawa Electric Corp., where he leads
the renewable energy business in the
areas of measurement and control.
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POWER February 2021

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