Do you have GETs? How Eversource is implementing grid improvement technologies to maximize electricity transmission for the benefit of customers

In recent years, as the federal government and states across the country have continued to adopt ambitious zero-carbon goals for their energy supply, climate change continues to cause increasingly severe and damaging weather patterns, and customer demand for energy continues to grow, one thing is certain: improving our energy grid is non-negotiable.

Significant upgrades and investments in transmission infrastructure are needed in the coming years to keep pace with growing electricity demand, electrification and the integration of the vast amounts of new clean energy sources that are expected to come online. The changing climate is also causing more severe storms and unusually severe weather that damage aging infrastructure and cause customer outages.

“At Eversource, we believe that our future is clean energy, and the future of clean energy starts with the grid,” said Bill Quinlan, Eversource president of transmission and offshore wind projects. “At the same time, using innovative hardware and software, we must ensure that we maximize the transmission of electricity in our existing system as we continue to build out our future clean energy grid.”

Enter network enhancement technologies, i.e. GET. It is a broad range of technologies that include sensors, power flow control devices, advanced conductors and analytical tools designed to improve the performance of the electrical system and provide benefits to customers.

Eversource has extensive experience with GET. In some cases, GETs are standard equipment at Eversource, meaning the vast majority of projects result in significant additional capacity to existing infrastructure. The company has been researching and using these technologies in its transmission systems for decades, some dating back to the 1980s. As part of the solution development and alternatives analysis process, Eversource evaluates GET and conducts a thorough cost-benefit analysis on behalf of its customers before implementing technology or software.

Projects over the past few years to rebuild transmission lines to replace aging infrastructure have resulted in ratings for individual lines increasing by 200-300%. This is because Eversource uses modern, high-temperature, low-sag conductors, which are the company’s standard conductor. Without this technology, it would be necessary to build two or three new additional transmission lines along the same corridor for each reconstruction project to achieve the same increase in capacity. Not only does the rebuilding of the line use more resilient structures that can withstand stronger winds and environmental damage, but the increased capacity of the line can be used for countless purposes – for example, connecting a new solar generator, which could result in significant utility tax bills. real estate and other local economic benefits.

Another example of GET is the successful commissioning and commissioning of the world’s first static grid-forming synchronous compensator, or STATCOM, which is a reactive compensation device capable of rapidly supplying or absorbing reactive current. This technology enables the safe and reliable operation of South Fork Wind, the nation’s first commercial-scale offshore wind farm, whose turbines were deployed from the New London State Pier.

STATCOM is used on the South Fork Wind project.
Loan: Courtesy of Eversource

This type of specialized STATCOM uses inverters enabling “grid forming” control. This emerging and promising technology offers numerous benefits in specific applications, such as the inherent ability to create and maintain voltage stability during unbalanced faults and extremely weak grid conditions. Most inverter-based resources use “grid-following” inverters that depend on the grid to provide a stable voltage and frequency reference. The benefits and capabilities of grid inverters are based on enormous research and industry research. Eversource has published technical articles in journals and given international talks on its best practices and lessons learned using this cutting-edge technology.

Installing cabling at the South Fork Wind substation.

GET can also be used in a number of ways to help meet carbon reduction goals. For example, “clean air” switches use purified oxygen as an insulating agent instead of SF6, a potent greenhouse gas. In December 2022, Eversource commissioned the first 115 kV clean air circuit breaker in the United States as part of a Preston substation upgrade package. In December 2023, Eversource also activated the world’s first 345 kV clean air circuit breaker at the Haddam Neck substation. These circuit breakers are important safety devices that help protect your system from damage from overcurrent while increasing system reliability and lowering your carbon footprint.

Jason Thomas (left) and Haseeb Rehman (right), two Eversource engineers who contributed to the design and engineering of the clean air switch project in Preston, Connecticut. Loan: Courtesy of Eversource

Eversource, in partnership with the University of Connecticut (UConn), has been selected as one of four grant recipients under a federal Department of Energy program to develop technologies that improve grid reliability, optimize power infrastructure and help connect the grid to renewable sources. One way Eversource is working with UConn on GET is to deploy new solar-powered DLR sensors along existing transmission lines in Massachusetts, which are critical to integrating and delivering new offshore wind energy.

DLRs help determine duct thermal performance more dynamically using improved, more detailed or real-time data. This is particularly useful when a large amount of energy – e.g. an offshore wind farm – is connected to the power grid and system operators need to determine the applicable current carrying limits for transmission lines. As more offshore wind projects come online over the next decade to help meet Connecticut’s decarbonization and clean energy goals, Eversource can learn from this key research to ensure DLR is effectively implemented and maximizes benefits.

In partnership with the University of Connecticut, Eversource plans to install non-contact DLR sensors on an existing 345 kV transmission line between two substations to optimize the nearby 800 MW Vineyard Wind offshore wind farm.
Loan: Courtesy of Eversource

“GETs allow us to maximize the use of existing facilities; future network plan; integrate new sources of clean, renewable energy more effectively into our electricity grid; and increase the resiliency and reliability of our customers,” said Jacob Lucas, Eversource’s director of transmission system planning. “While GETs are an important component of a modernized electricity grid that complements clean energy projects, they are not a one-size-fits-all solution and must be carefully assessed on a case-by-case basis. Our ultimate responsibility is to provide our customers with safe and reliable electrical services – in a cost-effective manner.”