Evaluating UWB for Wireless Clock Synchronization of an IEC 61850 Stand Alone Merging Unit

In recent years, electricity grids have undergone radical transformations in order to manage the increasing presence of Distributed Energy Resources (DER) as well as the increasing demand for electricity due to electric vehicle charging systems. The IEC 61850 standard, which introduced digital control architectures based on communication networks, marked a significant milestone in the management of primary substations and the entire electrical network in general. The Stand Alone Merging Units (SAMUs) are the elements that connect the analog sensors installed on the electrical network to the digital control systems of substations. The digitalization performed by SAMUs enables the virtualization of measurement and control functions, which are typically operated by dedicated components. The accuracy of information obtained from a distributed system, such as SAMUs, depends on the system’s ability to synchronize with an external source of time. Typically, SAMUs are synchronized via Global Positioning System (GPS) or networked solution, such as IEEE 1588. A novel wireless clock distribution method based on Ultra Wide Band (UWB) technology is presented and evaluated in this research. The experimental characterization highlights as the proposed approach is a feasible solution for clock synchronization of SAMUs: the phase error of clocks generated by two SAMUs synchronized via UWB is 17.5 ns.

I. Introduction

In the latest years, power grid management has undergone a radical transformation. The integration of Information and Communication Technology (ICT) solutions into electrical infrastructures has allowed a management improvement of the increasing presence of Distributed Energy Resources (DER) and the growing power demand due to the presence of electric vehicle recharging stations. The IEC 61850 [1] standard stands as a milestone of this revolution, which included digitalization of primary [2] as well as secondary substations and control systems based on communication networks.