New tech holds potential to unlock hidden grid capacity

Great River Energy is seeking to expand capacity of its transmission resources by testing an exciting new technology.

Following an internal planning study to identify lines with potential congestion and the highest financial impact, Great River Energy selected a transmission line in West Central Minnesota for a pilot project that uses Heimdall Power’s “Neurons.” These sphere-shaped sensors can be easily installed by autonomous drones or line technicians on energized high-voltage power lines to adjust the line’s capabilities to current weather conditions.

Great River Energy’s Hawick Service Center crew installed four of the sensors on the Morris to Johnson Junction line, near Morris, Minnesota, last September to collect and measure real-time data on conductor current, conductor angle, conductor temperature and weather conditions such as ambient temperature and wind speed. This data is transported by cellular connection and processed to understand the real-time capacity of power lines and ultimately increase the amount of electricity than can be transported across the line.

“We are laser focused on achieving our mission of providing affordable and reliable electricity to communities across the Midwest,” said Priti Patel, Great River Energy Vice President and Chief Transmission Officer. “This technology will help us unlock grid congestion and achieve additional transmission capacity from our existing infrastructure.”

Congestion can change by the minute and is based on a variety of factors, including scheduled transmission line maintenance and generation dispatch variability typically associated with wind generation.

In general, wind power production increases when wind velocities increase. Wind also has a significant cooling impact on transmission line conductor temperatures, leading to increased transmission line capacity of the lines near these wind generation resources. This enables increased wind power production and transfer using dynamic line rating (DLR) technologies.

Historically, Great River Energy has used static summer and winter line ratings derived from conservative estimations for weather and known equipment properties to determine line capacities. The new sensors allow Great River Energy to combine the conductor properties with real-time data for conductor temperature and ambient weather conditions to calculate a more accurate rating with the goal of increasing transmission line capacity.

Data gathered since the start of the pilot indicate the potential gains Great River Energy could realize through DLR, showing an increase of more than 25% capacity nearly 70% of the time. Great River Energy is still confirming its understanding of the total increased capacity, but the pilot indicates the potential for significant benefits on the chosen transmission line.

Michael Craig, Great River Energy supervising manager of energy and distribution management system, is pleased so far with the pilot project’s results and said Great River Energy will be adding sensors on four more lines this summer.

“This method is more accurate compared to seasonal ratings as it can use actual line conductor temperature to determine the capacity of the line and ensure the line isn’t becoming too hot,” Craig said. “We plan to deploy additional sensors along key congested lines where the line conductor acts as the limiting factor, aiming to curtail overall congestion costs for Great River Energy and our members.”

By understanding the real-time capacity of power lines, Great River Energy can optimize its transmission assets and set safe, new operational limits to keep costs low and integrate more resources, including renewable energy, into the existing grid.