New Approach for Measurement Data Handling in Cloud-Based Synchrophasor Systems for Smart Grids

The classical Wide-Area Monitoring System (WAMS) ischaracterized by a hierarchical architecture composed of Phasor Measurement Units (PMUs) and different levels of Phasor Data Concentrators (PDCs). The WAMS based on synchrophasor technology was originally designed for transmission systems; nevertheless, with the development of the smart grid paradigm, the benefits of this technology are being extended to the distribution network. Normally, PMUs send measurement data ata high and constant reporting rate to guarantee the monitoring of dynamic events in the electric transmission network.However, the typical communication systems expected to be used by distribution system operators will be generally shared and/or public and,in this case, the bandwidth available among PMUs and PDCs, or among the PDCs and the control center, is strictly dependent on the type of communication channel used and on thelevel of network traffic. In this context, a new transmission logic for thetransfer of data between PMUs and PDCs can be implemented. The strategy proposed in this paper is to increase the measurementreporting rate only when the electric system changes from a steady-state condition to a dynamic and potentially unsafe condition. The risk of losing important information related to the dynamic event is mitigated by sending the PDC measurements relating to pre-trigger events aggregated in the first data packet following the event detection.