Baltimore Gas & Electric has been involved in voltage conservation for more than four decades. But business as usual was no longer enough after the EmPOWER Maryland initiative was passed in 2008.
EmPOWER Maryland calls for the state's utilities to reduce energy consumption by 15 percent by 2015. As part of the program, the utilities were called upon to implement or accelerate their conservation voltage reduction (CVR) strategies, which involve bringing down and fine-tuning the voltage on circuits to save power.
BGE’s acceleration is still a multi-year endeavor, so it has not yet filed its full plan with the Maryland Public Service Commission. But part of the plan is in place.
The utility, owned by Exelon, has already piloted its house-developed software on six feeders and will expand that to ten to thirteen more later in 2014. Ultimately, it will deploy CVR across its entire distribution territory. The cost of the project and the voltage reduction factor have not been made public ahead of the PSC filing, which is expected soon.
"With approval, Baltimore Gas and Electric's CVR deployment will rival the largest projects in the United States to modernize monitoring and control of voltage and reactive power,” said Ben Kellison, director of grid research at GTM Research, adding that it will join the ranks of other utilities such as Duke's subsidiaries, California's investor-owned utilities, Oklahoma Gas and Electric and Dominion Virginia Power.
“It’s a little new for this space,” Michael Smith, lead engineer with BGE, said of writing software for distribution applications. Previously, most of the technology was deployed back at the substation, but BGE, like other utilities, is increasingly moving intelligence and sensoring onto the circuits and the end of the line.
"Moving sensors and intelligence further into the grid will certainly become a greater asset with time as the growth of distributed solar in BGE's territory will alter feeder characteristics, requiring more granular modeling and control of each phase on a feeder,” said Kellison.
Going it alone
For many distribution automation applications, there are scores of vendors offering sophisticated solutions to help utilities meet operational challenges. GTM Research expects the soft grid market to double between now and 2020 to more than $20 billion. The largest portion of that will be grid analytics, including asset management, grid optimization and outage management.
Targeting investment in energy efficiency and distributed energy through new data streams and software is just one of the topics that will be discussed at Greentech Media’s Soft Grid conference in Menlo Park, Calif. on September 10-11. Kellison’s panel will discuss in more detail the merits of distributed and centralized computing platforms for distribution grid applications that enable greater integration of solar, increase efficiency and improve reliability.
Many utilities are rethinking conservation voltage reduction, but BGE has a unique approach. Although BGE is installing smart meters, the meters are not central to delivering the next-generation voltage control, as they are with some other utilities.
For the most part, BGE doesn’t use load tap changers for voltage control. Instead, it has transformer tap changers at the substation and feeder capacitor banks, and has installed additional sensors on its feeders for volt/VAR control.
For the pilot project, BGE developed its own voltage software, since most of the vendors offered solutions tailored for load tap changers. “It’s more of a substation-based algorithm,” said Smith.
The utility worked with Cooper Power Systems and a Yukon capacitor voltage control system that uses BGE’s in-house algorithms to monitor and provide real-time feedback to the volt/VAR application. The voltage reduction comes from operating the capacitor banks so that the average voltage across all sensors is at a minimum. For the approximately 10 percent of the territory that does have load tap changers, BGE is working with OSI.
Smart meters, while not central, are also a part of the package. The advanced metering system is used to confirm the voltage at the end of the line. For the utilities that are using their meters for CVR, many are taking 5- or 15-minute interval data, but BGE found the ideal approach for its software would be to use 1-minute data collection intervals. Smith wrote in an analysis of the pilot that 1-minute data might not be realistic from the AMI system, which was not built with granular voltage data collection in mind.
The utility is looking at a product from its AMI vendor, Silver Spring Networks, that would allow it to receive a report from meters that hit a predetermined voltage sag, rather than constantly pinging meters for voltage reads. “We’re only interested in the bad actors,” said Smith. Otherwise, the utility may use a meter extension that can provide the same information via a cellular backhaul.
As the pilot expands across the entire distribution territory, there will be other tweaks that have to be made. BGE has found that certain devices, such as plasma TVs, use more energy when there’s a reduction in voltage. “We’ll continue to monitor it,” said Smith, adding that the project would not be deployed and then just left to run in the background.
There are already some additional benefits to the software, even though it is barely out of pilot phase. Data analysis showed that “it was not uncommon” for power factors to deviate substantially from the desired range, said Smith.
Once the algorithms are fully deployed and BGE is doing analysis on the whole system, it will be able to correct power factors. The utility also expects to minimize the number of daily operations using voltage regulators and load tap changers.
Working through a full deployment of CVR is a considerable undertaking for BGE, but the engineering team is also looking at other software applications that can support investment planning.
Another project with GRIDiant, for example, evaluates where to put fault circuit indicators based on financial costs and benefits. As the years go on, Smith said BGE would likely add even more projects that shift technology and analytics out of central control and the substation and onto the grid. “We’re just starting to move this out,” he said. “It’s a totally new space.”
For more on how utilities are leveraging data and analytics for planning and operations, join Greentech Media’s Soft Grid conference September 10-11, 2014.