IEEE Electrification Magazine - June 2018 - 47

IEMS: brain of the EI
ever since tomas dy-liacco proposed the architecture of
the eMS in 1967, the traditional eMS for ePSs has become
rather mature after more than 50 years of development.
the eMS played a central role in ensuring the safe and
efficient operation of the power grid and was known as
the brain for ePS operation.
But with the smart grid developing into the eI, the conventional eMS for the electricity power grid might also be
expected to evolve into a new brain, which is the IeMS
(Figure 5), an entity that satisfies the operation and control
requirements of an integrated energy system. the IeMS is
proposed to manage and control the multienergy flow in a
coalesced energy framework and ensure the safety, efficiency, and environmental friendliness of the whole structure. compared with the eMS for ePSs, the IeMS faces new
technical challenges, because it needs to manage many
different facilities from multiple energy sectors other than
ePSs. detailed technologies (see "For Further reading") are
omitted here due to space limitations.

Gas
Integrated
Energy System

Heating

Power

Figure 5. The IEMS, the brain of the EI.

Security
Assessment
and Control

Optimal
Dispatch

SCADA

Nodal Energy
Price

Architecture of the IEMS
there are several essential functions in the IeMS, such as
supervisory control and data acquisition (Scada), state
estimation (Se), security assessment and control, optimal
dispatch, and nodal energy price (Figure 6). It is noteworthy
that these functions are all developed not only for traditional ePSs but also considering different coupling energy flows
and energy-supply facilities so that the walls between different energy systems can be truly broken down.
the IeMS's multienergy flow Scada is based on Iot
technologies, with sensors collecting all of the necessary
data from different energy subsystems. It is used to realize
complete, high-performance, steady-state, real-time data
acquisition and monitoring. thus, it is the foundation of such
functions as security assessment and control and optimal
dispatch. the multienergy flow Scada provides the fundamental functions, including real-time data acquisition and
processing, alarming, automatic recording and printing, network topology coloring, event recall, and so forth. Furthermore, it supports the remote control of different kinds of
devices, such as feeder switches and transformer taps in ePS
distribution grids that include gas boilers, heat pumps,
valves in district heating network pipelines, compressors in
natural gas networks, and multiple storage devices, such as
ice storage, hot water tanks, and batteries.
the Se of the IeMS serves as a filter of raw data acquired
from Scada for providing a complete picture of the system's states and the identification of bad data. the ePS is, of
course, monitored by remote terminal units, phasor measurement units, and other intelligent electronic devices, the
automation level of which is very high. however, the monitoring and communication infrastructure of other energy
systems is not as advanced as in ePSs because of technical
and economic reasons. For example, in a district heating
system (dhS), only a few telemetered values of pressure,

Physical System of the EI

Figure 6. The architecture of the IEMS.

temperature, and mass flow at the supply or consumer
nodes are available, which hardly provide a complete picture of the system state.
Moreover, the sensor network occasionally generates
bad data in the monitoring process for several reasons,
such as meter failure, time skew, or communication noise.
these bad data, if not eliminated, will cause a gross error
in the real-time assessment and control modules. Se techniques have been widely used in ePSs, water distribution
systems, and natural gas systems for real-time monitoring or leak detection. In dhSs, Se is used to evaluate heat
loss and improve energy efficiency.
as for steam supply networks, which are very common
in industrial parks, we proposed a modeling and Se
approach considering the steam transport drainage process. We first proposed an Se approach for combined electricity and heat networks and combined electricity and gas
systems, in which the steady-state models for ePSs, dhSs,
and natural gas networks were considered, together with
coupling components, such as cooling, heating, and power
(chP) units; circulation pumps; and gas compressors. also,
we studied the pipeline dynamic that causes the largest
heat power transportation delay in dhSs and proposed a
two-stage Se approach for the integrated heat and electricity system. these technologies are all applied in the IeMS to
realize Se for the eI.
another basic IeMS function is security assessment
and control, which is able to enhance the security level, a

IEEE Elec trific ation Magazine / j u n e 201 8

Table of Contents for the Digital Edition of IEEE Electrification Magazine - June 2018