Technology Research Area:

Smart Sensors

What are smart sensors, and what do they have to do with TVA's mission?

Power delivery systems are among the largest investments for utilities. They are widely diverse and often located in remote areas. A high demand for power and budget restrictions are putting well aged transmission lines and substation equipment to the test.

Currently, a new technology is being developed that has the potential to boost management of utilities' assets, improve transmission reliability, eliminate unnecessary and dangerous maintenance, and create a smart transmission system.

TVA, the Electric Power Research Institute and other utilities are in the process of developing a new generation of low-cost, smart sensors that can monitor the health of power transmission and substation equipment in remote locations.

What is TVA doing about this technology?

TVA is investigating smart sensors that will help operators assess the condition and performance of power systems as they are operating. TVA has deployed over one hundred wireless sensors on substation equipment at the Paradise Fossil Plant in order to better understand

• how sensors perform in the substation environment
• communication and data collection issues
• data security issues
• power harvesting for sensor operations
• how to improve data visualization and operator interaction.

What are the possibilities for smart sensors?

A transmission system fitted with smart sensors should have the ability to monitor characteristic properties of power transmission components to evaluate their how they are working as they are actually in service.

Improved knowledge of the condition of equipment and the stresses it has undergone will let operators better manage the system. In addition to assessing the condidtion of the equipment, TVA expects to learn how to utilize it more efficiently.

For example, the electric load that circuits can carry is limited by temperatures reached along the transmission system. But these limits occur only a small percentage of time, while conservative fixed ratings are assumed to be limiting 100 percent of time.

Furthermore, only a relatively small percentage of transmission circuits are thermally limited. These circuits limit the useful transfer capabilities of the whole network by 10 percent to 20 percent. Monitoring of these relatively few circuits and applying ratings that change according to actual circumstances can increase the capability of the whole network substantially.

Higher dynamic ratings may be achieved if more-precise real-time knowledge about the condition of the components can be obtained from sensors. Increasing the ratings in this way would allow delivery of the maximum current that can flow without exceeding clearances or insulation ratings.