Feature When the first commercial coal-fired electric power plants came online, starting with the Holborn Viaduct power station that supplied electricity to the City of London in January 1882, the world was changed forever. Fast forward 142 years, and the world has changed a lot.

When it comes to the power grids that distribute electricity to homes and businesses, however, a lot less has changed. Sure, there've been tweaks added here, and there and new forms of electricity generation have been introduced, but by and large the design is the same.

Our current electrical paradigm isn't sustainable. In just 142 short years power generation from burning fossil fuels has changed the world's climate, necessitating yet another wave of electrification - this time from clean, renewable energy sources including solar and wind. With that new energy paradigm comes the need for a new grid, and with it a host of challenges to overcome. 

Sometime soon large, regional power grids supplied by a few solitary fuel-burning giants will hopefully be gone. In their place will be interconnected microgrids fueled by smaller distributed power generation plants, such as wind and solar farms, Dr Michael Ropp, an electrical engineer at the Sandia National Lab over in America, told The Register this week.

Rethinking the grid isn't simple. Grids are mostly designed with single one-way power lines feeding AC current from power plants to customers. Renewable energy sources like solar and wind typically produce direct current electricity, requiring an inverter to turn it into alternating current. All those distributed inverters spread over a whole bunch of small grids mean it's much easier for a grid to end up in a loop, as power flows in different directions among small, interconnected systems. 

Keeping a bunch of microgrids playing nice with each other - and not destabilizing due to the creation of unintentional closed loops - will be tricky, if not impossible, without a bunch of new tech. The US power system as it stands isn't designed for such decentralization.  

That's where Ropp and his fellow engineers at Sandia and its partner facilities come in. They've been working on methods to create the ideal self-healing power grid, and they think they've found a far more reliable way to do it than has been tried to date. This technology could be deployed anywhere, really, in theory and depending on the circumstances.

The modern self-healing grid: Not sci-fi, but not cheap

There's no need to wait for a future of electrical lines filled with self-replicating nanites for a self-healing grid to become a thing - it's not even a new concept. 

Development of such power-shifting systems has been a stated priority of Uncle Sam since the codification of the US Energy Storage Competitiveness Act of 2007, which was designed to spur development of a number of electrical innovations - self-healing grids among them. 

The US code defines a self-healing grid as one "capable of automatically anticipating and responding to power system disturbances, while optimizing the performance and service of the grid to customers." Such technology has even been deployed by power providers like Charlotte, North Carolina-based Duke Energy in several states. 

Duke's system is typical of existing self-healing grids. It involves "remote sensors and monitoring, as well as advanced communication systems that deliver real-time information from thousands of points along the grid … to make real-time decisions to keep power reliable," according to its website. 

Self-healing grid technology, said Duke, can reduce the number of customers affected by an outage, decrease the time necessary to locate a problem, speed up power restoration and reduce downtime due to natural disasters and other events. 

Of course, those advancements aren't without their own impediments. Such self-healing grid technology is expensive and - like the current grid - centralized. So a failure could knock the entire thing offline. 

Networks of fiber optic cables, monitoring equipment, and lots of other costly hardware is necessary to make self-healing grids like Duke's possible. Using traditional telecommunications to monitor the grid also means there's a potential for cyber attacks, and scaling such systems is a further problem.

"In a major problem situation of any type, you may lose those communications," Ropp told The Register. "And in some cases, those comms are expensive." 

With those drawbacks in mind it would be hard to justify wide-scale deployment of such self-healing technologies to modernize the grid - especially given so many clean energy projects are already behind schedule and threaten to derail clean energy goals. 

Ropp and his fellow researchers want to solve this problem by looking at ways to prevent the formation of closed loops without needing the total situational awareness provided by such self-healing designs. 

"We're trying to figure out how to avoid creating a loop if the only information I can see is the information right where I am," explained Ropp, emphasizing that a key goal is avoiding reliance on a system of expensive communications equipment. 

The future-future grid is already ready

Ropp and his Sandia-led team of researchers, with collaboration from boffins at New Mexico State University, have developed a method of detecting potential disruptions between microgrids using nothing but software algorithms. Better yet, the system doesn't require any new hardware, and could be readily deployed as relays - the microprocessor controls for grid switches that reconfigure electrical systems in various ways. 

"New software on existing hardware was our focus on this project," Ropp said. "Almost all of what we're doing is deployable on existing commercial hardware." 

As described in a pair of papers published in 2022 and 2023, Ropp and his team have sussed out a system that works at each relay switch - without any knowledge of the rest of a larger system of microgrids between which relays would form bridges. 

By looking at the frequency of voltages on either side of a relay and running the measurements through an algorithm, Ropp's software arrives at a correlation coefficient between the two sides that determines whether two microgrids should be disconnected to prevent a loop forming. 

Each microgrid relay, equipped with the necessary code to make that determination, could act independently to prevent grid malfunction. According to Sandia, those algorithms could be used to determine when a portion of a grid should be shut off to maintain power supplies to critical resources (like hospitals), and could reorganize to avoid damaged microgrids - much like the existing centralized systems in use by companies like Duke. 

With the hardware necessary for such a system largely in place, this isn't a distant, far-term project - it could be in place in less than five years, it's claimed. 

We've got the technology, we're ready to go with this

"We use a lot of existing functions that are already used in the power system - we just use them in new ways to try to detect new things," Ropp told us. "We came up with [the loop detector] ourselves to solve a specific problem, but the whole idea is that this is something that can be practically applied on power systems tomorrow. We've got the technology, we're ready to go with this." 

Of course, testing will be needed to ensure the preliminary results demonstrated in the papers bear out in the real world. "We want to pound the living daylights out of it to make sure that it really does work," Ropp explained. "We're confident, but we haven't done larger scale testing yet." 

The team is already setting up test facilities at Sandia, and has partnered with several utility companies around the US to ensure the concept works across different power system design philosophies. Ropp isn't sure where the tech may be deployed first, but suggested it could end up being tested in multiple locations, once validated in the lab. 

As for whether we can make the transition from our old centralized electrical paradigm to a world of distributed generation and microgrids, Ropp has faith we can, with the matter all boiling down to how affordable we can make it. 

"What we're trying to do is to create solutions that allow us to meet the challenge without breaking the bank," he declared, "and [the self-healing grid algorithm] is what that's all about." ®

https://www.theregister.com//2024/02/01/selfhealing_microgrid_sandia/