Synchrophasors: Smart Grid intelligence
Although the concept of smart meters providing information about the grid has been present for years, quality of measurements and reporting rates of these devices have proven to be inadequate for maximizing utilization of transmission assets, as well as foreseeing blackouts and brownouts. Synchrophasors (or Phasor Measurement Units, PMUs) on the other hand, provide a much better insight into the state of the smart grid and in turn help optimize grid efficiency and stability.
Synchrophasors introduce the concept of time-synchronized measurements, utilizing the precise time signal from GPS (Global Positioning System) satellites. Additionally, they significantly increase their sampling resolution compared to ordinary smart meters. Instead of reporting electrical RMS values in one or more second intervals, synchrophasors constantly measure voltage and current waveforms and report their vector values (amplitude and angle position of the AC signal), or phasors as they are called, up to 60 times per seconds. Not only is the reporting rate greatly increased, but the use of precise GPS signals also means that these values are perfectly synchronized in time across all devices - and this proves valuable for predicting blackouts.
Figure 1. Rotating synchrophasors indicate system deviations from the grid frequency
Motivation for the development of WAMSTER
WAMSTER project as a concept was established in 2009, as a way to provide a better platform for synchrophasor related research. As of 2013, most of the premises in the field of synchrophasor technology still remain the same: phasor measurement units and collected synchrophasor data are mostly being used only for situational awareness by utilities operators, without full integratio into the smart grid automation. For academic research, costs of entire synchrophasor systems and the necessary communication infrastructure remain the main reason for the relatively slow adoption of this exciting technology. Furthermore, in cases where R&D data is collected from synchrophasors which are proprerty of utilities, but researched by academic circles, relying on existing communication infrastructure opens technical and security issues which are costly and time consuming.
To remedy this, WAMSTER system was developed as a cost-effective, fast-to-deploy and simple-to-use solution. Utilizing lightweight portable phasor measurement units, GPRS mobile networks for communication and a cloud storage and analysis solution as a service, WAMSTER resolves many issues mentioned above. Since the first installation in September 2010, WAMSTER has proven effective and reliable for several small R&D teams and academic research projects.
Future of Syncrophasors
Full potential of synchrophasors as feedback devices in the automated smart grid has yet to be discovered. Various academic and R&D teams use these large amounts of data to create accurate grid models and find ways to prevent power swings before they happen. As already mentioned, most utilities currently using synchrophasor equipment are still using this data to improve their grid awareness and aid operator decisions in parallel with their existing systems, but the technology is rapidly being integrated into complete smart grid solutions going towards full grid automation.