A New Voice in the Smart Grid Dialogue: The Grid Itself
Written by Jay Giri
Let's hear what the Grid has to say about its own evolution, and the potential it sees locked away in all that data. The author puts on his sci-fi hat and imagines a conversation with the Grid about a specific technology – synchrophasors – and how they will change the way the Grid interacts with control room operators.
GIRI: What is your biggest challenge in working with grid operators?
The Grid: In a word: visibility. Issues arise every day that operators cannot visualize, or cannot visualize fast enough. Take "undamped oscillations" for example. Oscillations occur all the time, all across the grid. Nearly all oscillations disappear gradually over time. Ones that do not are a much more serious problem. If left unchecked, these oscillations can seriously disrupt the flow of electricity. Today's EMS operators cannot see these grid oscillations.
The visibility issue is not restricted to the confines of any one section of my network.
People refer to me as "the Grid." The idea of a single grid is accurate because over time, interconnections have created linkages between previously-isolated electrical networks. But, we also have to remember that my network has been artificially segmented for various jurisdictional or ownership reasons.
So, you now have multiple operators using multiple Energy Management Systems to simultaneously control and manage their adjacent sections of my network. Each operator's EMS provides information on their specific segment, but not their neighbors'.
Because of those interconnections I mentioned earlier, these segments are inter-dependent and can affect one another. Problems in Segment A can easily spill over into Segment B if its operator cannot see the trouble coming from the other segment and take steps to insulate his network. Issues can continue to spread quickly from segment to segment and trigger a series of cascading blackouts.
When this happened on the East Coast in 2003, estimates placed the cost to the U.S. economy at $6 to $8 billion.
Clearly, visibility is Job #1. But we also need to ensure we are providing control room operators with cross-border visibility.
How will synchrophasor data improve visibility?
Synchrophasor data is, without question, a game-changer.
Data captured by Phasor Measurement Units – or PMU's – will allow me to share more real-time operational data with control room operators who manage the interconnected grid. This data is a major improvement over what is possible with Supervisory Control and Data Acquisition – or SCADA – systems currently in use.
Each PMU will capture 12-16 unique synchrophasor measurements. These range from three-phase voltage and currents to frequency and rates of frequency change. The data will be time-stamped, geo-located and delivered to control rooms at sub-second intervals.
The real magic of synchrophasor data lies in its integration with enhanced EMS functions to create the next generation of Energy Management Systems.
Why is integration so important?
Let's revisit the "undamped oscillations" mentioned earlier.
Synchrophasor data will not only make these disturbances visible to operators, they will let me play a more active role in correcting them. Through a synchrophasor-enhanced EMS, I can suggest ways for operators to identify, isolate and correct a problem, and prevent it from spreading.
My network is becoming more sophisticated every day. New wind and solar farms are coming online, people are charging cars in their homes and businesses are generating their own electricity. In some cases, energy is flowing in a direction opposite of what we have traditionally seen.
In this dynamic environment, operators have precious little time to digest mountains of data and develop a timely, appropriate response. Synchrophasors provide raw information, and the EMS is the intelligent conduit through which I can empower them to respond faster.
In many cases, I may even be able to take immediate corrective action without having to involve the operator.
How will synchrophasor data enable "cross-border" visibility?
We've addressed operational visibility and EMS integration to make operators' lives a little easier.
The third leg of what I call the "Stool of Synchrophasor Benefit" is communication.
Visibility enabled by synchrophasor data can allow one operator to identify problems on a neighboring network and insulate their own system.
Synchrophasors provide wide-area monitoring capabilities. The sharing of data between utilities takes the concept a step further to maintain a steady and reliable flow of electricity across the interconnected grid.
Looking back to the East Coast blackout, it's easy to see how this can translate to cost savings.
What else should we understand about synchrophasors?
Truth be told, I am not performing as well as I could be.
Today, since operators cannot fully visualize my dynamic, fast-changing operating conditions, they are overly conservative in the limits imposed on my equipment. Synchrophasor data will provide operators with a more detailed picture of my conditions and allow them to run the network closer to its true operational limit.
This is another instance where synchrophasors deliver cost savings. By maximizing use of current systems, utilities can, in some cases, offset the need for costly new transmission expansion.
Where are synchrophasors today, and what's the path forward?
Through the U.S. Department of Energy's Smart Grid Investment Grants, more than $300 million is being invested today to increase America's number of installed PMUs from 200 to more than 1000. This trend in PMU growth is also taking hold throughout the world – in China, Europe, South America and Australia, for example. In China, two national utility groups are in the process of installing some 1500 PMUs.
With each PMU capturing 12-16 measurements, up to 60 times each second, operators will be armed with a degree of actionable visibility that is unprecedented in the history of grid management.
Ramping up PMU deployment is the key to unlocking the benefit of synchrophasor data, and letting me take a more active role in keeping society’s lights on!
Jay Giri, an IEEE Fellow, is Director of Power Systems Technology and Strategic Initiatives at ALSTOM Grid in Redmond, Washington, and an affiliate professor at the University of Washington, Seattle. In 1978, he and 11 other engineers co-founded Energy System Computer Applications (ESCA), which after numerous mergers became part of Alstom Grid in 2010. Previously, at ESCA, he designed and implemented the original software for an automatic generation control system that controls half of North American generation today, and a dispatcher training simulator that is used worldwide. He earned his doctoral degree at Clarkson University in New York, and his bachelor's at the Indian Institute of Technology (IIT), Madras. He is a member of the IEEE Power & Energy Society governing board.