This paper presents the design and the implementation of a servo-clock (SC) for low-cost Phasor Measurement Units (PMUs). The SC relies on a classic Proportional Integral (PI) controller, which has been properly tuned to minimize the synchronization error due to the local oscillator triggering the on-board timer. The SC has been implemented into a PMU prototype developed within the OpenPMU project using a BeagleBone Black (BBB) board. The distinctive feature of the proposed solution is its ability to track an input Pulse-Per-Second (PPS) reference with good long-term stability and with no need for specific on-board synchronization circuitry. Indeed, the SC implementation relies only on one co-processor for real-time application and requires just an input PPS signal that could be distributed from a single substation clock.
Cite
@article{arxiv.1902.09912,
title = {A Software-based Low-Jitter Servo Clock for Inexpensive Phasor Measurement Units},
author = {Pietro Tosato and David Macii and Daniele Fontanelli and Davide Brunelli and David Laverty},
journal= {arXiv preprint arXiv:1902.09912},
year = {2019}
}