Why Examine Communication Technologies
In order for sensors to be of value to transmission and substation managers, there must be a method for collecting and transmitting the data they collect. This data must be made available to end-users and applications in an accurate, secure, and efficient manner. Substations will become data hubs where data from within the substation and from nearby transmission line structures will be collected.
Methods of Communication
Data from sensors can be collected and transmitted in a number of ways:
- Direct: Sensors can communication back to a central location directly, using radio frequency satellite or cell phone networks. The approach is simple, yet expensive, to implement.
- Store and Collect: Sensors can store data as peak values or histograms until it can be collected during walking, driving, or flyby inspections. Data can also be collected by a transmission line robot. This approach doesn't require additional infrastructure and can be implemented along with existing inspections.
- Daisy Chain: Sensors communicate with one another along the transmission line until the signal reaches a hub or the base station. This approach doesn't require additional infrastructure but requires sensors to be closely placed.
- Wireless Mesh: Sensors communicate with multiple neighboring sensors to form a mesh with redundant paths. Communications are collected at a hub or base station. This approach doesn't require additional infrastructure but requires sensors to be closely placed.
- Wireless Hub: Sensors communicate wirelessly with a central hub located within two to three structures, which then communicates wirelessly to the base station.
EPRI is developing and assessing a wide range of communication and data collection technologies for use both within substations and along transmission lines.
- A project is underway to demonstrate the application of both permanent and temporary wireless sensor mesh.
- Technology demonstrations of components of the transmission line robot are underway with a prototype expected in 2012.
- Research is beginning into the application of unmanned airborne vehicles (UAVs) for uses including the collection of sensor data.
Challenges to data collection include the power required to transmit information; the number and spacing of sensors and communication technologies required; and the security and integrity of the data itself.