1588 Grandmaster on an SFP for Timing Synchronization in Power Utility Networks

Precision timing increases the efficiency and uptime of electric utilities by improving their monitoring and troubleshooting capabilities. IEEE C37.238- 2011 is rapidly becoming the global standard for power system automation, protection, control, and data communications over packet-switched networks. IEEE C37.238-2011, therefore, specifies IEEE 1588-2008, also known as PTPv2 (optimized for use in electric power industry network architectures) as the protocol to meet the synchronization requirements of most power systems applications. It is currently being considered for inclusion in IEC 61850 Edition 2.

IEEE 1588-2008 is a future-proof solution for power utilities because it meets timing accuracy needs for both today’s and tomorrow’s applications. Remarkably, it does so while reducing the cost of installing and maintaining a separate dedicated timing network (IRIG-B), since dedicated cabling for delivering synchronization to IEDs is no longer required. IEEE 1588, in contrast, transports timing synchronization information (packets) over the same cabling as data.

Protection and Control IEDs
Time syncronization is required for intelligent electronic devices (IEDs) to perform fault recording, sequence of events recording and any other functions that require information from IEDs to be time-stamped. When events and timing are recorded in the proper chronological order, pre-fault, fault and post-fault events can be accurately analyzed. Usually, protection and control IEDs have an internal clock resolution of 1ms. The typical requirement for time synchronization in IEC 61850 substation automation systems, however, is to guarantee 1ms time-stamping accuracy for the station bus and less then 1μs time-stamping accuracy for the process bus. With IEEE 1588-2008, this requirement can be achieved much more cost-effectively than it was using legacy IRIG-B solutions.

IEEE 1588-2008 and Phasor Calculation
Synchrophasors are devices that were developed to measure the state of the electrical power grid and manage power quality. Phasor measurement units (PMUs) evaluate electrical wave data at given locations in the power system (substations) and calculate a comparison of two values at different locations synchronized to absolute time. The IEEE C37.118 standard defines and determines communication between synchrophasors and how they should be time-stamped and defines timing accuracy in terms of microseconds. In a packet-switched network, the only solution for doing so is IEEE 1588 v2.

RAD’s Synchronization Solution for the Power Grid
RAD’s Service Assured Networking (SAN) solutions are ideal for upgrading IEDs and PMUs to the IEC 61850 standard, or when IEEE 1588-2008 is used for any other synchronization application. These SAN solutions are based on RAD’s innovative MiCLK, an SFP-based IEEE 1588 Grandmaster with a built-in GNSS receiver. The finger-sized MiCLK enables timing over packet (ToP) by instantly upgrading any existing substation network device to the IEC 61850 standard. This eliminates the need to install bulky, standalone GNSS (GPS/GLONASS/BeiDou) receivers at every substation site, reduces power consumption and operational costs and eliminates additional “points of failure” while providing highly accurate timing distribution for any network element requiring phase or Time of Day (ToD) synchronization.