IEC/IEEE 61850-9-3
IEC/IEEE 61850-9-3 (Power Utility Profile) or PUP is an international standard for precise time distribution and clock synchronization in electrical grids with an accuracy of 1 μs. <BR>It supports precise time stamping of voltage and current measurement for differential protection, wide area monitoring and protection, busbar protection and event recording. <BR>It can be used to ensure deterministic operation of critical functions in the automation system. <BR>It belongs to the IEC 61850 standard suite for communication networks and systems for power utility automation. IEC /IEEE 61850-9-3 is a profile (subset) of IEEE Std 1588 Precision Time Protocol (PTP) when clocks are singly attached. IEC/IEEE 61850-9-3 provides seamless fault tolerance by attaching clocks to duplicated networks paths and by support of simultaneously active redundant master clocks. For this case, the extensions to PTP defined in IEC 62439-3 Annex A apply. Main features. IEC/IEEE 61850-9-3 uses the following IEEE Std 1588 options: Performance. IEC/IEEE 61850-9-3 aims at an accuracy of better than 1 μs after crossing 15 bridges with transparent clocks. <BR> It assumes that all network elements (bridges, routers, media converters, links) support PTP with a given performance: By relying on these guaranteed values, the network engineer can calculate the time inaccuracy at different nodes of the network and place the clocks, especially the grandmaster clocks suitably. <BR>IEC TR 61850-90-4 (Network engineering guidelines) gives advice on the use of IEC/IEEE 61850-9-3. IEEE 1588 settings. IEC/IEEE 61850-9-3 restricts the parameters of IEEE Std 1588 to the following values: Local time distribution. For applications that do not use the corresponding function in  IEC 61850, the grandmaster may distribute local time (e.g. for human display) using the ALTERNATE_TIME_OFFSET_INDICATOR TLV as specified in IEEE Std 1588 §16.3. Standard owners. This protocol has been developed 2012-2014 by the IEC SC65C WG15 in the framework of IEC 62439-3, which applies to all IEC industrial networks, as PTP profile L2P2P (Layer2, peer-to-peer). To avoid parallel standards in IEC and IEEE in the field of grid automation, this work has been placed under the umbrella of the IEC&IEEE Joint Development 61850-9-3. Technical responsibility rests with IEC SC65C WG15, which is committed to  keep the IEC 62439-3 profile L2P2P and IEC/IEEE 61850-9-3 aligned.