SEAPAC 2011
CIGRE Australia Panel B5
Sydney 10-11 March
SEAPAC 2011 Ref29 O'Reilly Oong
Enhancing Systems Stability using Synchrophasors
Robert O’Reilly
Cooper Power Systems
Robert.Oreilly@cooperindustries.com
Matthew Oong
Cooper Electrical Australia
Matthew.Oong@cooperindustries.com
Keywords: Synchrophasor, PMU
1
Abstract
Enhancing Systems Stability using Synchrophasors
The concept of Phasor Measurement Unit (PMU) or Synchrophasors has been around for
many years. The Global Positioning Systems (GPS) is providing an absolute time reference
that is allowing a wider deployment of PMU’s allowing measurement across a large portion of
an electrical grid to be combined in new meaningful ways.
In this paper we will look at some real applications
Initially The Eastern Interconnect Phasor Project now also part of the North American
Synchrophasor Initiative (NASPI) was first primarily used for the collection of PMU data and
transmission of this information to the Tennessee Valley Authority (TVA) for the eastern
portion of the United States with Bonneville Power handling the Western part of the US grid..
More recently, applications have evolved to implementing real-time controls using wide area
measurement and real-time controls systems. An example of this is where PMU data is
received from the PMU’s located within three main areas within the Hydro-Quebec grid. A
portion of the information not being provided by the PMUs are grouped together to create a
synchrophasor virtual data stream so that this information can be correlated the real PMUs
providing the base information and allow for real-time control actions to be taken.
In other applications, the advent of wind turbines being connected directly to the distribution
network has created great interest in using PMU data for island management and
reconnection to the grid especially in remote regions where power is only available via small
diesel generator systems in these remote areas any savings in the use of the diesel fuel helps
also on the environmental side.
We will also be presenting some of the trends that we are seeing around the world in how this
information is being looked at and more especially what will this serve in the long term.
Another area worth discussing is new requirements for more frames per second, utilities are
starting to plan collecting at much higher frequencies and use this information for more rapid
real-time control of instabilities being sensed on the grid.
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SEAPAC 2011
CIGRE Australia Panel B5
Sydney 10-11 March
SEAPAC 2011 AbstractRef29 OReilly Oong
Enhancing Systems Stability using Synchrosphasors
2
Introduction
Phasor measurement is a measurement of the magnitude and phase angle of Voltage /
Current of the electrical waveform coordinated with GPS (Global Positioning Satellites) timing
to ensure that all data is relevant in the proper time frame.
Phasor Measurement Unit (PMU) or Synchrophasor is the generic name given to the
Intelligent Electrical Device (IED) that undertakes this measurement from the physical
quantity via VT and CT and converts this data into an information stream in a predetermined
format /protocol i.e. (IEEC37.118).
With the advent of the Global Positioning System (GPS), now an absolute time reference is
easily available across large areas, this allows the proper comparison of information within a
selected time window to be able to perform correlation, analysis and control which could not
be properly conducted in the past (because of incoherent time information of the different
readings) accuracy in microseconds is required within such systems.
In developing a phasor measurement network, a number of Phasor Measurement units can
be connected to a Phasor Data Concentrator (PDC). This is typically connected into the
Supervisory Control and Data Acquisition (SCADA) system to display the real-time
information in regards to overall changes of the grid stability.
There are significant benefits of having this information available to operators, planners;
power quality information to enhance the quality of their decisions with better timely
information. More importantly is the use of this information with the state estimators for
predicting and planning grid stability.
Cooper Power Systems first involvement with Phasor measurement was delivered in 2006.
When Hydro-One required a Phasor Data Concentrator to collect, concentrate and store
information locally, with this data also being sent to the Tennessee Valley Authority (TVA) as
part of the Eastern Interconnect Phasor Project. Overall, this is known as the North American
Synchrophasor Initiative on which utilities, vendors and different organizations work with.
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SEAPAC 2011 AbstractRef29 OReilly Oong - final.doc
SEAPAC 2011
CIGRE Australia Panel B5
Sydney 10-11 March
SEAPAC 2011 AbstractRef29 OReilly Oong
Enhancing Systems Stability using Synchrosphasors
3
Quebec Wide Area Measurement and Control
In 2008 and 2009 Hydro Quebec started the development and implementation a real-time
control using wide area network synchrophasor measurement and real time control systems.
The driver of this work, was to reduce inter network oscillations between two large generation
sites separated by long distances. The network reinforcement created because of the major
ice storm in the early 2000, created a ring around the island of Montreal, however with
operation it had been noticed that this introduced network stability issues due to the long
distance of transmission from the generation in the north and east to the load centres in the
south of the Province of Quebec.
3.1
Geography
This above picture provides an overview of the geographical distances between the two major
generating sites and their relationship with the Montreal Ring (Montreal being the largest city
in the province of Quebec) and hence uses a large amount of power from these two
generating sites.
James Bay area in the north is comprised of 8 Hydro-electric generating sites providing a total
of 16,121 MW’s
The Manicouagan area is comprised of 7 Hydro-Electric generating stations with a total
generating capacity of 5,635 MW’s.
Churchill Falls generating facility ties-into the Manicouagan generating area providing an
additional 5,429 MW’s of power (distance between these two sites is approximately 550)
miles.
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SEAPAC 2011 AbstractRef29 OReilly Oong - final.doc
SEAPAC 2011
CIGRE Australia Panel B5
Sydney 10-11 March
SEAPAC 2011 AbstractRef29 OReilly Oong
Enhancing Systems Stability using Synchrosphasors
3.2
System Architecture
There are five substations between James Bay Falls Generating Area and Montreal and four
substations between Manicouagan Generating Area and Montreal
At each substation there is a Substation Phasor Data Concentrator.
The syncrophasor data is sent to the Phasor Data Concentrator at the Main Control Centre in
Montreal from three main PMU’s at James Bay, Manic and Montreal.
The Synchrophasor data is sampled at a rate of 60 samples per second and synchronised to
the nearest microsecond.
A virtual Phasor Measurement Unit stream is created from using key information provided
from the Montreal Ring, this information is then also inserted into the overall Phasor Data
Concentrator.
The Phasor Data Concentrator creates the PDC frame to be broadcasted to the different
SPDC’s on the network, the control algorithms are being executed and the control information
if any are required is inserted into the PDC frame that will be sent back to the different
SPDC’s.
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SEAPAC 2011 AbstractRef29 OReilly Oong - final.doc
SEAPAC 2011
CIGRE Australia Panel B5
Sydney 10-11 March
SEAPAC 2011 AbstractRef29 OReilly Oong
Enhancing Systems Stability using Synchrosphasors
3.3
Substation Phasor Data Concentrator
The Substation Phasor Data Concentrator receives packets of data (and commands) from the
main Phasor Data Concentrator and sends the relevant commands to the Substation
Synchronous Unit control equipment.
The Substation Phasor Data Concentrator receives acknowledgements and status
information from the Substation Synchronous Unit and transmits the local voltage
measurement to the next Substation Phasor Data Concentrator on the transmission system.
3.4
Packet Information
Table 2 below shows the data packet from the Phasor Data Concentrator to the Substation
Phasor Data Concentrator / Substation Synchronous Unit Controller in the IEE C37.118
format. Of note is Field No 10 and 11 where additional information is provided to create the
virtual stream.
Table 3 below shows the command packet from the Phasor Data Concentration to the
Substation Phasor Data Concentrator / Substation Synchronous Unit Controller in the IEE
C37.118 format. Of note is Field No 7 where the commands are being sent based on logic in
the Phasor Data Concentrator performing real time logic
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Sydney 10-11 March
SEAPAC 2011 AbstractRef29 OReilly Oong
Enhancing Systems Stability using Synchrosphasors
Table 4 below shows the command packet from the Substation Synchronous Controller to the
Phasor Data Concentrator. Of note is Field No 7 where the status and alarms are being sent
to the Phasor Data Concentrator, this extra-frame capability of C37.118 provides for
interesting capabilities within the context of this protocol for providing additional information in
regards to status and control information.
Wide-area control relies on transmission of measurements over long distances and the
availability of long transmission links may be lower than classical electrical links in the
substation used for local control. The proposed strategy therefore uses a fallback control
based on local measurements, giving a fraction of the benefit of those attainable with the
WACS. In order to feed the control system with local measurements, the SPDC has to add
local information from IEDs and relays to the remote measurements from the PDC and send it
to Substation Synchronous Unit (SSU). The shunt compensator primary control is made of a
Static Var Compensator (SVC) controlled by an Automatic Voltage Regulator (AVR). The
secondary control is made of the SSU, which is responsible for the choice between local and
global control, and the Power System Stabilizer (PSS). Figure 2 depicts the data flow in the
application.
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SEAPAC 2011 AbstractRef29 OReilly Oong - final.doc
SEAPAC 2011
CIGRE Australia Panel B5
Sydney 10-11 March
SEAPAC 2011 AbstractRef29 OReilly Oong
Enhancing Systems Stability using Synchrosphasors
Generation Area 1
Control Substation
PMU 1
IED
Relay
Network Control
Center
PDC
SPDC
SSU
PSS
Generation Area 2
PMU 2
AVR+
SVC
SCADA +
Operator
Table 5 : Data types and sample rates for this specific application
Sending device
Phasor Measurement
Unit
SCADA measurement
Operator commands
Central Phasor Data
Concentrator
Substation Relays
Substation IED
Substation Phasor Data
Concentrator
3.5
Receiving device
Central Phasor Data
Concentrator
Central Phasor Data
Concentrator
Central Phasor Data
Concentrator
Substation Phasor Data
Concentrator
Substation Phasor Data
Concentrator
Substation Phasor Data
Concentrator
Substation
Synchronous Unit
Protocol
IEEE C37.118
Sample rate
60 samples / sec
IEC 60870
6 samples / sec
IEC 60870
On demand
IEEE C37.118
60 samples / sec
IEC 61850
60 samples / sec
IEC 60870
2 samples / sec
IEEE C37.118
60 samples / sec
Phasor Data Concentrator Software Architecture - Tools
The Phasor Data Contrator and the Substation Phasor Data Concentrator are based on
Cooper Power Systems SMP Platform.
This platform allows various physical connections (RS232, RS485 and or TCP/IP)
between the PMU(s) and the Phasor Data Concentrator.
The Phasor Data Concentrator is communicating to the PMU and the Substation Phasor
Data Concentrator via IEE C37.118 and its Master Station via IEC60870-5-104. The
Automation logic was developed in an IEC61131 Soft PLC Environment. Table 5
provides a list of the different interfaces used and the different sampling rates used.
Page 7 of 11
SEAPAC 2011 AbstractRef29 OReilly Oong - final.doc
SEAPAC 2011
CIGRE Australia Panel B5
Sydney 10-11 March
SEAPAC 2011 AbstractRef29 OReilly Oong
Enhancing Systems Stability using Synchrosphasors
A specially developed PDC Function was created to allow System Wide Data Recording
into Comtrade file format. Using an in-built configuration tool any point of information
within the Phasor Data Concentrator can be used as a trigger for data recording of raw
data and or computed data points. The configuration tools allows configuration of the
pre and post trigger time’s independently and the system is capable of recording six
simultaneous events.
Hydro Quebec required that the systems provide a performance time of 8 ms from data
reception to data sent out to other systems. This could easily be verified by the inbuilt
logs available in the Phasor Data Concentrator with an overall performance in control
mode of 16 ms.
Page 8 of 11
SEAPAC 2011 AbstractRef29 OReilly Oong - final.doc
SEAPAC 2011
CIGRE Australia Panel B5
Sydney 10-11 March
SEAPAC 2011 AbstractRef29 OReilly Oong
Enhancing Systems Stability using Synchrosphasors
4
Distributed Generation Islanding Management
A new evolving area is in the use of synchrophasors is in the area of distributed
generation. More and more we are seeing much smaller wind farm sites (less than
25MW) being tied directly to the distribution network in remote areas (where there is no
transmission level system voltages) this to provide power other than mostly diesel
generation units and of their heavy dependency on this fuel).
The challenge being when there are a number of very small distributed generation sites
within a small area each of the generation systems do not have major capabilities to
provide overall stability in this type of application, where the use of PMU units and PDCs
at all of the generation sites coming back to a central system has become a very
interesting solution for local stability with the of renewable energy solutions within these
small localised systems.
5
Trends
We are currently seeing trends into three main areas:
a) Applications based where utilities are starting to develop for small distributed
generation environments, especially in regards to small wind farms and their
integration directly into the distribution network and especially in regards to better
management of islanding generation scenarios, real time wide area management and
control in local grids, regional transmission and super interconnected grids.
b) The performance of PMU where Utilities utitilies are starting to require more
information for eg high sampling rates up to 240 samples per second for a 60 HZ
frequency .
c) The availability of new IEDs (relays) with integrated PMU functionality, this is helping
tremendously when implementing new technology that the utilities can now purchase
their standard protection relays with integrated PMU capabilities and hence providing
new ideas for the use of this type of information.
To this end we have supplied three large systems in 2009 to EPRI to be part of their Smart
Grid Laboratory research and developing integration of synchrophasor technology with 61850
for the Smart Grid of the future.
6
Conclusion
Enhancing system stability using Synchrophasors is today a reality. This paper has shown
two different discussions of applications where utilities are undertaking real time control using
Phasor Data Concentrators over a large geographical area and in the context of distributed
island generation. Off the shelf technology is currently available to meet some of these
requirements, but however there are the requirements for more research to fully understand
and start developing better and more sophisticated algorithms within a more unified
coordinated environment.
Page 9 of 11
SEAPAC 2011 AbstractRef29 OReilly Oong - final.doc
SEAPAC 2011
CIGRE Australia Panel B5
Sydney 10-11 March
SEAPAC 2011 AbstractRef29 OReilly Oong
Enhancing Systems Stability using Synchrosphasors
References
WPRC 2010, Spokane, WA, USA - Development and Testing of Phasor Data Concentrators
for a Wide-Area Control System, authors : Charles Cyr - HQ, Innocent Kamwa - HQ, Robert
O’Reilly - Cooper, Sebastien Rolle - Cooper
Page 10 of 11
SEAPAC 2011 AbstractRef29 OReilly Oong - final.doc
SEAPAC 2011
CIGRE Australia Panel B5
Sydney 10-11 March
SEAPAC 2011 AbstractRef29 OReilly Oong
Enhancing Systems Stability using Synchrosphasors
Biography
Robert O’ Reilly - Senior Application Engineer
Cooper Power Systems (Energy Automation Solutions)
Mr. O’ Reilly has been involved in the development of different technological applications in
numerous industries for more than 35 years with 20 of these years within the power industry.
During this period he has participated in the writing of more than 25 technical papers, ranging
from applications in different industrial sectors in regards to automation, control and protection
systems. Mr. O’ Reilly has also been guest speaker for numerous engagements with
universities and graduate level conferences, including key-note speeches at international
conferences. He has also produced a number of articles for different technological magazines
for the energy industries among others.
Matthew Oong – Regional Sales Manager
Cooper Electrical Australia (Cooper Power Systems)
Mr. Oong has been involved in Power Distribution and Industrial Automation for more than 25
years. His initial training was with the former Sydney County Council’s Test Branch, where he
undertook the Electrical Engineering Certificate and Bachelor of Engineering (Electrical). Mr.
Oong worked for Rolls Royce Industrial Power as a Commissioning Engineer, Design
Engineer and Project Manager before moving into Automation Sales with Rolls Royce Paklog
and Siemens. He has had a number of Sales Management roles at Siemens and Otis. At
Cooper Industries Mr. Oong is responsible for Cooper Power Systems Energy Automation
business in Australia and New Zealand.
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