IEEE Electrification Magazine - June 2017 - 80

Asset
Protection
Management
and
and Maintenance Control

HMI

Gateway,
Cybersecurity

Application
Functional
Blocks

Microgrid Controller
Power Mix Management

61850 Plug and
Play Goose
Support
Field
Control
Unit

Field
Control
Unit

Layered
Control Local
Intelligence

Electrolysis

District Heating

Power at Low Price

DG
H2
Storage

Power at High Price

Fuel
Catalysis

Figure 6. A schematic of the digital EMS platform provided by GE. HMI: human-machine Interface, DG: distributed generation.

Initially, the study and identification of the EMS architecture are required. Then, per the project requirements, the
application functions in the EMS will be identified, investigated, designed, simulated, and validated. A schematic of
the digital EMS platform is shown in Figure 6. The developed application function blocks (AFBs) will be implemented in one of the GE digital automation platform controllers.
The controller will be tested in a real-time environment

Table 2. The characteristics of centralized

(using hardware in the loop) to mimic how it will operate
at the real site. In the final stage, the microgrid controller
will be deployed at the NTU Eco Campus and at REIDS
Semakau Island to interface with and coordinate a selection of existing local energy resources, energy storage
devices, different types of load, and so forth. It should be
noted that the microgrids at the Eco Campus and on
Semakau Island belong to different segments (private and
stand-alone), and so the implemented
AFBs may be different.

and decentralized control structures.

Centralized Control

Decentralized Control


E
lements in the microgrid operate
normally with common goals.

T
he ownership of DERs and loads
is not diverse.

T
he devices can accept and follow
the central controller's command.

T
he number of DERs and loads is
generally limited.

I
t has a fast communication system
and a set of sensors.

I
t searches for the optimal or
near-optimal solution.


T
he microgrid operates in a market
environment and requires competitive operation from DERs and loads.

L
ocal DER owners may be diverse
and have their own objectives.

E
ach device's controller has a
certain degree of independence and
intelligence.

T
he number of DERs and loads is
normally high.

A
dedicated communication system
may not exist.

S
uboptimal solutions to the microgrid objective may be accepted.

I
t allows for new DERs and loads
plug and play.

I E E E E l e c t r i f i c ati o n M agaz ine / j un e 2017

Control System Structure
The microgrid can be operated in a centralized or a decentralized mode. Table 2
summarizes the characteristics of both
control structures. Considering the size
of the microgrids on both sites, the ownership of the DERs and loads, the control
hardware properties and constraints,
and the objective of this EMS, centralized
control is chosen as the EMS control system structure in the PMM project.

Digital Platform of the
Proposed Control System
The GE controller is an embedded device with versatile processing power,

Table of Contents for the Digital Edition of IEEE Electrification Magazine - June 2017