Coordinator: Paul Wright

The state of the art of PMU technology has been progressing rapidly, placing new and demanding requirements on the PMU metrology infrastructure. Reflecting these changes are two amendments made to the standard IEEE C37.118.1 which have introduced dynamic tests in addition to static tests for PMUs. Also, the future use of PMUs in distribution networks will require higher phase accuracy devices which must be made traceable. Finally, the recent development of commercial calibrators for PMUs has created a need for calibration capabilities for such instruments.  

The two recent amendments of IEEE C37.118 introduced and refined requirements for dynamic tests in addition to the static tests described in the 2005 version. This early version of the standard was used as a reference during the planning phase of the SmartGrid I project. The dynamic tests were introduced after it was observed that many PMUs compliant to the standard, performed poorly in the field. This led to serious compatibility difficulties between PMUs produced by different manufacturers. The cause of these discrepancies was the original misconception that power waveform parameters (magnitude, phase, frequency) remain steady in power networks. The realisation of this led to the development of dynamic tests. The inclusion of these tests in the metrology infrastructure will call for changes of its hardware and software. 

While originally designed for wide area monitoring of high voltage transmission networks, PMUs are likely to be used in the future in distribution networks containing embedded generation such as photovoltaic or fuel cells. In such systems, the role of PMUs will, similarly to transmission networks, be used to monitor and control of stability. Because of the shorter distances of distribution networks, the phase variations will be much smaller. Additionally, the level of power quality disturbances such as harmonics and inter harmonics are much higher in such networks. Therefore, PMUs used in distribution networks will require a much higher phase resolution as well as being more robust to power quality disturbances. The metrology infrastructure will need to be upgraded in order to ensure the traceability of this new generation of PMUs.     

Commercial calibrators for PMUs have been developed over the years and are now increasingly commercially available. As the penetration of PMUs increases, such calibrators will typically be acquired by network operators or commercial test laboratories for routine calibration of PMUs. The calibration of these calibrators will be typically made by manufacturers and / or national metrology institutes (NMIs). This again challenges the capability of the PMU metrology infrastructure which was primarily aimed at PMU calibration. As PMU calibrators are 4 to 10 times more accurate than PMUs, the accuracy of the PMU metrology infrastructure must be increased accordingly and become up to 100 times better than the IEEE C37.118-2013 requirements on PMUs. 

 This project provides the NMIs in Europe with a PMU metrological infrastructure well beyond the present state of the art in PMU technology and in line with future industry needs. 

For more information, see  the project webpage >>