［ A Case Study of the Installed System ］

Construction of Experimental
Power Grid Centre (EPGC)
Keywords

Saburo Maehira,
Yoshinobu Ueda

MicroGrid, MicroGrid Central Controller, Distributed energy resource

Abstract

The Experimental Power Grid Center (EPGC) was completed and ofﬁciallyopened on 1st November 2011. EPGC is the program under Institute of Chemicaland Engineering Sciences (ICES), a research institute under The Agency for
Science Technology and Research (A★STAR), Singapore to research and develop
the new technologies for intelligent and decentralized power distribution, interconnection and utilization.
EPGC is an experimental power grid facility with the total capacity up to1MW. There are three buses which can be conﬁgured as independent, serial,parallel, looped conﬁguration.

±30s, 90kW ±30s

1 Preface( 4 ) Lead-Acid (LA) Battery: 110kWh( 5 ) Lithium-ion Batteries (Li1, Li2) : 2 × 20kWh
The following equipment are provided as programmable emulators that enables various experiments.
( 1) Power Grid Emulator (PGE) : 90kW 4 quadrant( 2 ) Wind Turbine Emulator (WTE) : 10kW
( 3 ) Programmable Load Banks (PLB) consist ofthree unit of 50kW, 150kW and 300kW

Meidensha Corporation delivered along with thebuilding a central controller for the grid, Distributed
Energy Resources (DERs), and emulators for theExperimental Power Grid Center (EPGC) and it
opened on 1st November 2011.
This facility is provided with a three-phase fourwire bus over the entire length. Distributed energy
resources, such as renewable energy and electricalstorage systems and various simulatedload equipment are connected to the 3phase 4 wire bus. The experimental
Transformer
22kV/
1000kVA
415V
Singaporegrid can simulate the various distribuPower GridEmulator(SPPG)
tion networks.
90kW
22kV
4quadrant
10kW
In this paper, we report on theTransformer
22kV/
PGE
WTE
MicroGrid Central Controller (MGCC)
2500kVA
415V
to manage the entire Experimental GridPCC
PGE PCCsystem.

2 Conﬁguration of EPGC
Grid Central Controller
Fig. 1 shows the conﬁguration ofthe Experimental Grid system at EPGC.
Distributed Energy Resources are composed of the following equipment.
( 1) 3 Diesel Generators (DG) of 40kW,
100kW, 200kW( 2 ) Photovoltaic (PV) System: 60kW
( 3 ) Ultra-Capacitor ( EDLC) : 60kW

415V 3phase 4wire 3000A 50Hz
BUS A
415V 3phase 4wire 3000A 50Hz
BUS B
415V 3phase 4wire 3000A 50Hz
BUS C

MGCC

Monitoring andcontrolling

PLBLoadMicroGrid BUS
LIDGPVEDLC

LALiB

40kW
100kW
200kW

20kW × 3

60kW ±30s
90kW ±30s

110kWh20kWh × 2

Distributed Energy Test System (DETS)
415V 3phase 4wire 1000A 50Hz

Fig. 1

Configuration of MicroGrid

Power systems composed of MicroGrids, various distributed energy resources, anda MicroGrid supervisory control unit (MGCC) used for these is shown.

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The EPGC Grid can be operated
MGCC
MicroGrid & Loads
Forecastingin both Grid connected mode where itOperationis connected to the supply network andplanningin islanded mode. The grid can be
MicroGrid Status
DER
operated using the PGE which allows aLoad
P (kW), Q (kVar)
Controller
statusF (Hz), V (V)change in voltage and frequency.
Therefore, this system can be used forexperiments that simulate the power
P (kW)P (kW)
control
control
P (kW)
Run/Stop
PLB
system conditions to verify the control
F (Hz) V
Q (kVar)controlcontrol
control
controland protection systems for DERs.
In grid connected mode it is necNegative
Electrical storage
essary to continue to supply stable
Renewable(PCC P, Q)[EDLC, LA, LiB]
PCC
energyDG
current
power to the target load using multiple[PV, WTE]
value
MicroGrid
Local following
DERs. Therefore,a constant power conBUS (F, V)
controltrol at PCC has been implemented. On
Positivethe other hand, in islanded operation it
DER status (Fault status, Power, Battery SOC)
DERs
is necessary to maintain a constantvoltage and frequency. In order toFig. 2 Control flow of MicroGrid Systemachieve these goals, the system conThe diagram shows the control of distributed energy resources from the MGCC andtrol is performed by combining the conthe MicroGrid control conducted by the power storage system.
trol by the optimal operation planning
pattern and Real-time load following
control with the load following control by electricalstorage system. Fig. 2 shows the block diagram ofthe system.

3 MGCCMGCC is a computer system for monitoring
and controlling of the whole facility MicroGrid EPGC,
Monitoring facility of MGC is the 22kV distribution
system in EPGC, 415V low-voltage system, distributed energy resources and simulated equipment,
as shown in Fig. 3.

3.1 Controlling for MicroGrid
In grid connected operation, it sends the power
output command to distributed energy resourcefrom MGCC in accordance with the pattern of optimal operation plan that is created every hour. The
grid central controller implements the real-time load
following control for distributed energy resourcewith a period of 5 seconds while continuously monitoring the status of the power ﬂow at PCC. It controls the power at PCC in the following period tocomplement the difference between the load demandand ﬂuctuation of renewable energy power of the day.
In Islanded operation, DG is a source of voltage
and frequency in this Grid, which has a drooping
characteristic. Therefore, the frequency in theMicroGrid will ﬂuctuate depending on power output

08

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Fig. 3Single Line Diagram GUI of MGCC

A supervisory screen of the MGCC is shown. This screen is used
for the supervisory control of electrical facilities in the EPGC asa whole.

of DG. The central controller will monitor the frequency in the micro-grid at all times, it control to thediesel generator so as to keep the frequency at 50Hz.
In the transition operation, the control is carried out to regulate the voltage of the diesel generator to be the same as the voltage of the coming
power grid system.
Fig. 4 shows the GUI of MGCC. MGCC hasfour controllers,, it is possible to operate four simultaneous MicroGrids within EPGC.

4 Postscript
In this paper, we introduced overview of anexperimental grid and its controller developed
based on Meidenʼs expertise in Microgrids.
This project paves the way for future collaborative research with EPGC in area of MicroGrids.
・All product and company names mentioned in this paper arethe trademarks and/or service marks of their respective owners.

Fig. 4MicroGrid Setting GUI of MGCC

A setup screen of the NGCC is shown for the operation of theMicroGrid.

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