smart grid (chombosan/

Smart grid research on Chattanooga's muni-broadband network

Chattanooga's 10 gigabit-speed fiber-optic network has been a national example of a successful municipal-owned broadband service, and now it serves as a test bed for smart grid research.

Chattanooga’s network started as an effort by the city’s Electric Power Board to build a smart grid that could reroute power during outages and also carry internet traffic.  After receiving $111 million in funding from the Department of Energy, the service was up and running by September 2009.

Now, a partnership between EBP and Oak Ridge National Laboratory is collecting real-time sensor data that will allow the grid to see fluctuations immediately and can balance the electrical load in response.   

The sensors are collecting not only electrical system operation measurements but also a wide range of additional parameters -- from environmental to grid cybersecurity – that are being deployed on the network, according to an ORNL report.

As part of a proof of concept, ORNL worked with EPB to install sensor arrays at substations around the perimeter of the municipal utility’s 600-square-mile service territory. The devices provide real-time data on environmental factors such as sunshine, temperature, humidity and wind as well as the presence of chemicals such as methane and hydrogen. They also monitor for vibrations, radio frequencies and coronal discharge. While monitoring environmental conditions, the sensors also provide physical and cybersecurity situational awareness that can detect cell phone signals, the presence of drones, sensor network cyberintrusion attempts and physical intrusion.

The data about the grid’s operating environment is fed into EPB’s supervisory control and data acquisition (SCADA) system, and the city's fiber network makes transmitting data back to EPB’s control room reliable and nearly instantaneous.

At this phase, the testing is helping the researchers determine which sensors "make the most sense to implement on a larger scale,” EPB Manager of Smart-Grid Development Jim Glass said.

Sensors across town, for example, might indicate an approaching storm, which would affect solar-based electricity generation.  “If we get just 15 to 30 minutes of warning about cloud cover moving in with the sensors, that will get us a better idea of what to expect out of solar generation over the next hour or so,” Glass said.

In addition to the stationary sensors, EPB and ORNL are studying how drone-mounted sensors can help improve system reliability. Not only can they easily and safely inspect transmission lines, structures and other equipment, but they can also measure electromagnetic and coronal fields and sense chemicals and smoke.

To ensure the network and its embedded sensors are safe from internet-of-things attackers, ORNL researchers are working with EPB network and grid engineers to get the electricity grid off the internet and onto secure private networks.  A project is underway that demonstrates the design goals in an operating utility’s electrical, communications and data services.

“It is difficult to overstate the important role of cybersecurity in the communications link between such deployed sensor systems -- be they stationary in a substation or mobile on a vehicle or drone—and the core security of the embedded systems," said ORNL  Energy and Environmental Sciences Directorate researcher Peter Fuhr.  "Electrical disruptions due to cyberattack, such as experienced in Ukraine in 2015, are a constant reminder of the need for a robust overall cybersecure infrastructure.”

Going forward EPB will continue to serve as a testbed for ORNL's smart grid work as part of the Grid Modernization Laboratory Consortium. The utility's goal is to create a system using smart sensing, advanced metering, smart switches, customer software and other solutions that can identify and isolate problems and automatically reroute power to reduce or avoid outages.

“It reminds me of the installation of our fiber-optic system," EPB Director of Strategic Planning Lilian Bruce said.  "Once that was in place, we were able to leverage a lot of services around it. All the technologies we’re working with seem to be aligning.”

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