The operations and planning rules for integrating variable resources aren’t the same across the electric power industry in the United States at present. Opinions are somewhat divided about what...
Demonstrating the Smart Grid
Pilot projects clarify the vision of an intelligent utility system.
and placing data-gathering devices in two substations and five feeders. Behind-the-meter technologies, including thermostats and plug-based devices that interact with network signaling, are being installed as well.
“There’s not a single solution for all the homes,” Carlson says. “We’re testing different vendor solutions with different capabilities across the city.”
Phase II will be completed in April 2009, with meters installed at another 10,000 homes and businesses, and communications devices installed on another three substations and 17 feeders. At that point, testing, evaluation, and fine-tuning will commence for a yet-to-be-determined period of time.
In June, the consortium will assemble its substation and distribution automation network, which includes connecting to each customer and integrating the first set of meters. By September, a web portal interface will be established to let customers view their consumption. That will be followed by providing automated device control and management capabilities.
“There are obviously a lot of parallel paths,” Carlson says. “The first job is to install and test the new meters. Then we have the time-of-use rate proceedings, which begin in August. At the same time we have to examine the grid algorithms, document the key data points and identify potential gaps in the distribution system to determine the best way to establish a real-time data collection system. By August we should have the basics in place.”
Xcel estimates the project will cost roughly $100 million, with much of that borne by a combination of government grants, partners, and vendors looking to test and prove their software and hardware products.
“We’ve run our time data architecture requirements by companies like Oracle, SAP, Teradat, OSIsoft and they’re all interested in doing a trial,” Carlson says. “Everybody says they have technology that can be applied to this project. How much really exists and how much of it still needs to be developed? Right now we think 60 percent of the data architecture technology is already there, while the other 40 percent will probably need tweaking. Then we’ll determine what is or isn’t scalable.”
Xcel’s smart-grid-city project is intended to address a number of important smart-grid theories and questions. For example, the company believes monitoring a distribution system in real time to optimize power factor performance and system balancing could reduce distribution losses by as much as 30 percent. Therefore, it will retrofit existing substations with remote, near real-time data monitoring equipment to optimize performance.
“Say the grid is overstressed and we can see that a substation transformer is overheated to its breaking point. And because of that, we know we have a 15 percent power factor loss at that point in the system,” Carlson explains. “Our hypothesis is that if you have a fully-integrated grid, you can make distribution alterations to relieve that stress point and bring the loss down to something like six to ten percent. We believe we can do that system-wide.”
The goal is to create an intuitive electrical network, one that can incorporate and automate existing load-shedding processes to balance the system. Some of the necessary capabilities already are in place, such as remotely