Design of a Time Dissemination System Using Chirp Modulation for Medium Voltage Smart Grid Applications

• The monitoring and the management of smart grid require an advanced communication infrastructure. The time synchronization is among the most important services such an infrastructure should offer. Several solutions are available to disseminate the time information in a distributed system; for instance, most of the times a global positioning system (GPS) receiver is used to recover accurate time information. However, GPS receivers need a clear view of the sky. Other solutions, like the use of a network-based synchronization mechanism, require a dedicated communication infrastructure, which is not always feasible for economical reason. Thus, the use of the power grid itself to disseminate a time signal is extremely interesting. The aim of this article is to investigate the possibility to distribute a time signal over a medium voltage (MV) grid using a chirp-based modulation. The timing data are coded using IRIG-B time code. Such an approach does not require the installation of a dedicated infrastructure, and it is noninvasive, because the signal is transmitted on a different band with the respect to power line communication (PLC). The effectiveness of the approach has been experimentally evaluated on a test MV line available in a laboratory. Although the tested chirp-based symbol has a limited frequency bandwidth (80 kHz), the jitter in the identification of the start of frame is on the order of 7.5 μ s, fulfilling the requirements of the most smart grid applications. © 1963-2012 IEEE.

Nyckelord

Chirp modulation

IRIG-B

medium voltage (MV) distribution grid

smart grid

time synchronization

Carrier transmission on power lines

Distributed database systems

Global positioning system

Smart power grids

Communication infrastructure

Frequency band width

Global positioning system receivers

Medium voltage grid

Power line communications (PLC)

Smart grid applications

Synchronization mechanisms

Electric power transmission networks

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