Over the past month or so, Dominion Voltage Inc. (DVI) has announced new customers and expanded software for its technology to fine-tune conservation voltage reduction (CVR) systems using smart meter data.

At the same time, it has quietly sued a competitor, claiming it is violating DVI’s patents on the same concept -- an accusation that could spread to other industry players using smart meters to help manage voltages as the edges of the grid.

Last month, the subsidiary of Virginia utility Dominion Resources filed a lawsuit claiming that Alstom Grid is infringing on DVI’s patented approach to tapping smart meters for CVR purposes. The lawsuit, filed in U.S. District Court for the Eastern District of Pennsylvania, specifically names patent Nos. 8,577,510 and 8,437,883, which as described in the complaint, appear to hold pretty broad claim over the very idea of using distributed sensors for grid voltage management.

“Before others in the power transmission industry, Dominion conceived of improved technologies needed to more effectively and efficiently implement power distribution system control,” DVI’s complaint states. “The Dominion Patents are directed to controlling components of electrical power in a power distribution system using sensors at a plurality of distribution locations within the distribution system.”

That’s the technology behind DVI’s EDGE control platform, now in use by utilities across the country, and using smart meters and networks from a list of vendor partners including Silver Spring Networks, Elster and Landis+Gyr. But it’s far from the only advanced metering infrastructure (AMI)-based voltage management system being tested, as this GTM Research map of similar projects indicates.

Smart meters are valuable tools for CVR, because they provide a critical piece of intelligence for the task of lowering grid voltages to save energy: the endpoints. Distribution grid voltages tend to drop as the distance from the substations increases, but utilities have a responsibility to provide minimum voltages for all customers, even those on the farthest ends of the lowest-voltage lines.

Smart meters can provide alerts or alarms to help utilities avoid pushing any customers below voltage limits, or identify where voltages can go still lower, both with a greater degree of certainty than model-based, centrally controlled CVR schemes. They can also provide data from multiple meters to create estimates of voltages on other parts of the grid, as well as other aspects of real-world grid operating conditions.

But according to DVI’s lawsuit, at least one of the vendors working on this seemingly common idea of using smart meter data to inform grid operations is infringing on its patents. “On information and belief, Alstom Grid incorporates Dominion’s patented power control technology in Alstom Integrated Distribution Management System (IDMS) and its Load and Volt/VAR Management (LVM) module,” the lawsuit states, and “at least one utility has licensed this technology.”

DVI is seeking damages “adequate to compensate it for the infringement but in no event less than a reasonable royalty,” according to the lawsuit. This indicates that DVI’s goal is not necessarily to shut down Alstom’s implementations for utilities including National Grid and Duke Energy, but perhaps to get paid for them.

DVI’s lawsuit doesn’t specify just what aspect of Alstom’s approach to using “sensors at a plurality of distribution locations” for volt/VAR management is alleged to infringe on its patents -- and for now, the company isn’t elaborating. Todd Headlee, DVI’s CEO, declined to comment on the lawsuit in an interview earlier this month, beyond saying that the company intends to protect its investment in its intellectual property.

An Alstom spokesperson declined to comment on the lawsuit when reached this week. Alstom’s website describes its load and volt/VAR management platform as a system that “will select meters that it wants to receive voltage measurements from, as well as Brownout Voltage Alarms to guide and limit CVR control moves,” and that “as distribution connectivity changes, new meters are dynamically selected based upon the most extreme simulated voltage drops.”

It’s unclear whether DVI’s patent claims might extend to the many other companies working on linking smart meters and distribution grid voltage management. But the list of potentially affected parties is long. Ben Kellison, grid research director for GTM Research, noted that companies including Alstom, Survalent, Aclara, Itron, Utilidata, and ABB/Ventyx are either actively using voltage data from AMI to enhance CVR performance or are planning on it. Some may use smart meters as a key source of voltage data on the edge of the grid. Others, such as Utilidata, provide their own grid-deployed, networked sensor devices to pull voltage data, but could supplement what they do with smart meters or other distributed devices.

Earlier this month, Greentech Media learned that at least one other company involved in AMI-enhanced VVO has received a letter from DVI regarding its patent claims, though it wasn’t made clear whether or not the letter threatened legal action. DVI’s Headlee declined to comment on the letter when asked about it earlier this month.