The Tennessee Valley Authority is the nation's largest public power provider serving approximately 9 million consumers in seven southeastern states. The organization also happens to be a big supporter of open-source projects, including Hadoop, a tool designed for deep analysis and transformation of very large data sets.
Earlier this year, the Tennessee Valley Authority (TVA) announced that it open sourced its data system used to collect data from smart grid devices called Phasor measurement units (PMUs). The data collection system is known in the industry as a Super Phasor Data Concentrator (SuperPDC), which can be used to determine the health of a power grid.
The open-source version of the SuperPDC is now called the "OpenPDC." I spoke to both Ritchie Carroll (RC), the project's creator, and Josh Patterson (JP), the person responsible for introducing Hadoop to the project, to discuss what the OpenPDC is and why TVA turned to Hadoop in building the system.
What sort of data volumes are you working with? RC: Currently there is around 20 TB of archived data, we expect this to grow quickly as a result of the SmartGrid stimulus funding which includes the addition of 850 phasor measurement devices. This may well grow the archive to half a Petabyte within the next few years.
How is this data currently captured and managed? Is any data discarded? JP: Data is collected directly from field devices at 30 times per second. This data is then time-aligned and processed in real-time--all data gets captured into a binary data file as time-series data for mass processing by Hadoop.
RC: No data is currently discarded, if we get to the point of needing to discard data because of cost--this will be a decision based on weighed importance of collected data. It is likely the data around major events will never be deleted because it will always be valuable for future student researchers. There is also value in being able to go back in time and look for newly discovered event signatures to see how long they might have been occurring. … Read more