Presented by Dr. Christian Dufour at OPAL-RT RT15 User Group event in Berkeley on May 13-14, 2015

1. 1
Christian Dufour, Ph.D.
Opal-RT Technologies
christian.dufour@opal-rt.com
ARTEMiS-SSN Features for
Micro-grid / Renewable Energy Source Integration
using Real-Time Simulation
(NASPI Workshop presentation with some additions)

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Advancements in the Real-Time Simulation
of Large Active Distribution Systems
for PMU testing
Christian Dufour, Ph.D.
christian.dufour@opal-rt.com
March 24, 2015, San Mateo, CA, USA
Revision 2

3. 3
• Show how real-time simulation technologies can help utilities and
researchers to develop and test PMUs and PMU applications
• Show different solver for Digital Real-time Simulator (DRTS) such as:
• Real-time Phasor (or Transient Stability) Simulation
• Real-time Electromagnetic Transient Simulation
• Special solver solutions like SSN for distribution systems.
• Show communication features of real-time simulator
• Support of IEC-61850 protocols (Sampled Values, GOOSE)
• Support of DNP3 protocol
• Support of IEEE C37.118 protocol for PMUs
• Example cases from actual users.
Presentation Objectives

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Different solutions for different problem sizes
Real-Time
Transient
Stability
(or Phasor)
Simulation
(like PSS/e) Real-Time
ElectroMagnetic
Transient
Simulation
(like EMTP)
CPU-type
FPGA-
type
{
Opal-RT provides solutions for real-
time Transient Stability simulation
• ePHASORsim solver
• Sample time =1-10 milliseconds
Opal-RT also provides solutions for
real-time Electromagnetic Transient
Simulation:
• Hypersim and eMEGAsim with SSN
• Sample time= 10-100 µs
20 cores PC-based DRTS

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• Biggest actual client case so far: 30000 busses (positive sequence)
• Support for 3 phase modeling. (More important in distribution grids)
• METIS routines used to partition admittance matrix for calculation on
many processors
Real-Time Transient Stability with ePHASORsim**
** V. Jalili-Marandi, E. Robert, V.Lapointe, J. Belanger, “A real-time transient stability simulation tool for large-scale power systems”.
2012 PES General meeting, San Diego, USA, July 22-26, 2012.

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• Transmission line delays
allow large transmission
system to run in real-time.
• Ex: HQ grid run in real-time
on 128 core on SGI computer
• Automatic partition in
Hypersim RT simulator
Challenge of distribution networks with EMT-DRTS

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• Transmission line delays
allow large transmission
system to run in real-time.
• Ex: HQ grid run in real-time
on 128 core on SGI computer
• Automatic partition in
Hypersim RT simulator
• There is no such ‘long’ lines
in distribution systems!
• Cannot parallelize tasks like
in transmission grids
Challenge of distribution networks with EMT-DRTS

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State-Space Nodal (SSN) Solver for Parallel EMT RT-sim
• Reducing the node number is critical for DRTS because the LU factorization of Y
admittance matrix is an order O(R3) problem (R is rank of Y)
• SSN allow user to select the node location and limit the number of nodes.
• Less partitions make it easier to solve the equations on parallel cores,
without algorithmic delays.
Comparison of node number for standard nodal admittance method and SSN
Using EMTP/RTDS/Hypersim: 10 nodes, 16 ‘partitions’ Using SSN: 1 node, 2 partitions!
** C. Dufour, J. Mahseredjian , J. Bélanger, “A Combined State-Space Nodal Method for the Simulation of Power System Transients”,
IEEE Transactions on Power Delivery, Vol. 26, no. 2, April 2011 (ISSN 0885-8977), pp. 928-935

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Parallel State-Space Nodal Solver (SSN)
• SSN allow the parallelisation of the network equations without delay.
• How is this possible? Reducing the node number has the effect of creating much bigger branch
equations. These SSN group equations are computed on many CPUs in parallel!
• Note that this would be possible in theory for standard EMTP but in would be practically
inefficient because of the inter-core communication costs for a large number of branches.
SSN groups computed mostly in parallel
LU solution is made
on a different core

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Extending the real-time EMT simulation with SSN
• SSN node aggregation and parallel calculation capabilities pushes the limit of
real-time simulation of distribution grids
• ENEL Distribuzione, 750 nodes*, 52 µs ** France Distribution, 650 nodes*, 70 µs
**
** C. Dufour, S. Alma, S. Cuni, G. Scrosati, G. Valvo, G. Sapienza, "Renewable integration and protection studies on a 750-node distribution
grid using a real-time simulator and a delay-free parallel solver", CIRED-2015, Lyon, France, June 15-18, 2015
* Node definition may change these figures.
** Timing obtained using Intel-Xeon Processor-E5-2687W Xeon V3 and only 6 cores out of 20 available

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SSN in More-Electric-Aircraft
(Bombardier Global Express)
• GLEX stats:
• 25 SSN groups
• 109 switches (all coupled)
• SSN admittance matrix size: 48x48
• Time step 39 µs
0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5
14
16
18
20
22
24
26
28
30
Time (s)
Voltage(V
DC
)
SPS 1us
SPS 50us
SSN 50us
L. Montealegre Lobo, C. Dufour, J. Mahseredjian, “Real-time Simulation of More-Electric Aircraft Power Systems”, Proceedings
of the 15th European Conference on Power Electronics and Applications (EPE’13 ECCE Europe), Lille, France, Sept. 3-5, 2013

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Micro-Grid demos in SimPowerSystems
(new in R2015a)
http://www.mathworks.com/examples/simpower/4226-simplified-model-of-a-small-scaled-micro-grid
• Micro-grid composed of:
• Main source with breaker
• Feeder transformer
• Solar panel
• Battery with SOC and control
• Loads with profiles/breakers
• Native phasor solver can be used to study medium term energy availability
• SSN could be used to study transient behavior of the system with a real controller

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• DNP 3 (Distributed Network Protocol)
Supported Protocols (list not exhaustive)

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• DNP 3 (Distributed Network Protocol)
• IEC-61850
• IEC-61850-8-1 GOOSE
• IEC-61850-9-2 Sampled Values
Supported Protocols (list not exhaustive)

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• DNP 3 (Distributed Network Protocol)
• IEC-61850
• IEC-61850-8-1 GOOSE
• IEC-61850-9-2 Sampled Values
• C37.118-2005
(Synchrophasor protocol)
• IRIG-B for GPS synchronization
• More than 100 virtual PMU allowed
• IEC60870-5-104 (for SCADA systems)
• Modbus, Modbus-TCP
• OPC (Open Platform Communications)
Supported Protocols (list not exhaustive)
Image curtesy of MEINBERG Radio Clocks GmbH
https://www.meinbergglobal.com

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• EPFL in Switzerland developed an ultra-
precise PMU for distribution systems
• Validation was made with real-time simulated
IEEE 13 Bus test feeder system using SSN
• Node voltages/currents are send by the analog
outputs of the DRTS.
• Read by the prototyped PMUs (11 total)
• Other PMUs simulated in the DRTS.
• 100 softPMU possible. 30 tested as of May 2015
• Produce IEEE C37.118 stream which are gathered
by the Phasor Data Concentrator (OpenPDC)
PMU development and testing in the lab using DRTS**
** C. Dufour, J. Bélanger, "On the Use of Real-Time Simulation Technology in Smart Grid Research and
Development", IEEE Transactions on Industry Applications, Volume 50, Issue 6, Nov/Dec 2014.

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• KTH researchers build a complete WAMPAC laboratory with eMEGAsim DRTS
• Connects to physical PMUs, relays, other PDC streams, portable visualization tools…
Complete WAMPAC laboratory with DRTS (SmarTS-LAB)
Almas, M.S. ;Baudette, M. ; Vanfretti,
L. ; Lovlund, S.; “Synchrophasor
network, laboratory and software
applications developed in the
STRONg2rid project”, 2014 PES
General Meeting Conference &
Exposition, Washington, USA, 27-31
July 2014

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• Another group of researchers at KTH, Sweden, developed a test platform to
validate PMU performance and IEEE C37.118 standard compliance.
• Can connect both virtual and physical PMUs.
• Many applications developed such as on-line mode estimation and WAMPAC.
Synchrophasor test platforms with DRTS
Zhu, K., Deo, S., Al-Hammouri, A., Honeth, N., Chenine, M. et al. (2013) “Test Platform For Synchrophasor Based Wide-Area
Monitoring and Control Applications”. ,IEEE PES General Meeting Vancouver 2013

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• Iterative MOV enable precise real-time fault testing
• Unique feature in the DRTS market in SSN and Hypersim
Iterative methods in real-time simulators
C. Dufour, O. Tremblay, “Iterative Algorithms of Surge Arrester for Real-Time Simulators”, 18th Power Systems
Computation Conference (PSCC 2014), August 18-22, 2014, Wroclaw, Poland.

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• The increased power of multi-core PC is enabling even more powerful testing
methods for modern transmission and distribution grids.
• Transient Stability (TS) and Electromagnetic Transient (EMT) methods available in RT
• Coupled with efficient circuit solvers like SSN, we can now simulate
distribution grids of 750 nodes without algorithmic delays in EMT
• Node count simply follows Moore’s law, with new PCs.
• Transmission network (with long transmission lines): no size limits a priori. Hypersim can EMT
simulate the entire grid of the Province of Quebec on SGI with 128 cores.
• ePHASORsim: like PSS/e but in real-time.
• Actually support PSS/e files.
• Sized for 50000 nodes max in 2015, following Moore’s law.
• Communication protocols are important to make RT-sim of modern grids
• Opal-RT simulators support communication protocols like C37.118 and IEC-61850
Conclusion