Rate of Change of Frequency - a Power Quality Descriptor

The smart grids paradigm includes newly defined real time control strategies, and therefore detailed models for the energy transfer are required together with new algorithms for information retrieval. Although today measurement infrastructure (including the high reporting rate measurement devices, like Phasor Measurement Units) is capable to give insight to such details, the measurement information has to be structured in a new way. Moreover, new quantities - like rate of change of frequency - rocof - become relevant for both monitoring and control purposes. Presently there are in use aggregation algorithms inherited from power quality standards like the IEC 61000-4-30 set, but no algorithm is yet specified for rocof reporting. In this paper is presented a discussion of the time- and space- aggregation of frequency (including its rate of change) using phasor data concentrators' framework.