Characterization of Analog Front-End in PMU Design for Inertia Monitoring

In modern power systems, the measurement infrastructure is subject to ever more demanding performance requirements and operational conditions. In this context, the design of a Phasor Measurement Unit (PMU) involves different aspects, from the development of a software routine till the optimization of the hardware components. The recent literature has widely discussed the former aspect, while the latter has been typically considered as a mere selection of suitable devices and components. In this paper, instead, we take into account a PMU specifically designed to produce not only the traditional synchrophasor, frequency and rate-of-change-of-frequency (ROCOF), but also indices accounting for the results' reliability and the network stability. In such a demanding scenario, it is necessary to characterize and minimize any uncertainty contribution. To this end, we carry out an extensive assessment of the systematic and random contributions related to the analog front-end and the synchronization mechanism of the PMU. The experimental results show how the PMU accuracy is highly dependent on the quality of its acquisition stage and outline a set of reasonable performance targets in low-inertia power systems.