Eversource Transforms Direct Transfer Trip with LTE

Eversource evaluated a number of cellular solutions for this application. As the team
worked through evaluation, it realized that to achieve the level of reliability they
would need, they had to have a router that would support multiple cellular carrier
networks.

Eversource developed a solution using a combination of SEL’s RTAC and Sierra Wireless’ MG90 cellular gateway to get the situational awareness it needed.

Eversource selected the AirLink® MG90 because it enables two cellular carrier connections in each router. Eversource can select one cellular network as “primary,” but in circumstances where a connection cannot be established on the primary network, the MG90 automatically selects and switches to the secondary cellular network. The switching happens automatically and transparently. When the primary cellular connection is reestablished, the router is switched back to the primary in real time. This multi-cellular capability provides the reliability Eversource needs. 

“While the dual carrier aspect of the MG90 was a critical part of our decision, the AirLink® Connection Manager (ACM) was equally important for security. With the increasing cyberattacks on utilities, Eversource needed to ensure that all these communications could be protected via a virtual private network (VPN). The ACM sets up the VPN when the cellular connection is established, and automatically moves that encrypted tunnel to the new cellular network as required,” explained Tim Callahan, Senior Engineer, Distribution Standards at Eversource. “With the MG90 and ACM, we have the availability, latency and reliability we need to make this viable as the communications solution to support all the new renewable sources coming onto our network. Being connected to each of the “inputs” we have complete situational awareness of energy coming onto and leaving the grid, allowing us to effectively balance supply with customer demand.”

The sites that have been installed are up and running well and Eversource is in the process of deploying the new solution across its operating regions. 

“The SEL RTAC and MG90 combination is going to be a great solution for our distribution management system (DMS) – safely bringing renewables onto the grid and enabling us to manage supply and demand effectively. We’re seeing new applications that make the packaged solution a building block for future grid operations,” said Callahan. “We are now looking at how it will help us in dynamic volt VAR optimization and DSCADA operations, also with electric vehicles, modelling and forecasting and streamlining distributed generation interconnection processes.” 

Eversource is now examining integrating AirLink® Mobility Management into their operations. “With us using the RTAC and MG90 combination for each renewable source, we’re going to need a way to manage all these remote devices, and being able to have an on-premises system to do this makes sense,” said Callahan. 

Many utilities are struggling to bring new generation sources to the grid, and Eversource sees the RTAC and MG90 package as a solution to the challenge. “We’re talking to other energy companies regularly and they are all looking for better ways to bring in new supplies safely.” Eversource credits its team of engineers – from protection and control, IT telecom and SCADA teams to making this solution a reality. Our team’s efforts to make this a great solution is really a credit to the talent of our team and the superior technology of our partners like Sierra Wireless and SEL,” explained Callahan.