IEEE 1588 Time Synchronisation and Data Flow Assessment for IEC 61850 based Power Transmission Substations

  • Mingyu Han

Student thesis: Phd


Substation automation systems (SAS) in accordance with IEC 61850 are gaining popularity in the power industry and is expected to dominate the design of substations worldwide in the near future. The standard offers a 'future-proof' solution for the protection, automation and control (PAC) systems with cost reduction in design, operation and maintenance. IEEE 1588 Precision Time Protocol (PTP) is widely considered for use in IEC 61850 based substations due to its achievable sub-microsecond accuracy over Ethernet, which satisfies the accuracy required by sampled value (SV) process bus and other advanced PAC applications. However, PTP is still not considered by many utilities to be a fully-mature technology for reliable time distribution in substations. The propagation delay variations of PTP messages caused by network traffic are sometimes suspected of resulting in unacceptable timing errors. Substation engineers also require sufficient understanding of the PTP timing principle and the characteristics of network devices to operate and maintain the system. Additional investigations are needed urgently to study the characteristics of communication network behaviours in the presence of all principle IEC 61850 traffic. Confidence must be given to the system operators that the intrinsic data flow interactions in the well-designed substation automation system does not degrade the performance of either time synchronisation or other PAC applications. This research focuses on the use of PTP for precision timing, and interactions between multi-protocol substation traffic. A hardware test platform consisting of commercially-available products (e.g. clocks, Ethernet switches, merging units and protection relays) was designed and built to explore the performance both at the individual component level and at the complete substation automation system level. Testing tools including a traffic generator / network impairment emulator, a time synchronisation measurement server, an OMICRON test set, a network capture card and an Ethernet tap were integrated into the test platform to simulate several network conditions in both electrical and data communication systems. These network conditions were critical to fully understand the network characteristics and identify performance boundaries. The results systematically demonstrate that it is feasible to implement PTP as an alternative for conventional dedicated timing systems. PTP can be used in conjunction with seamless redundancy protocols as defined in IEC 62439-3 to enhance the system reliability while still maintaining a sub-microsecond accuracy requirement. Meanwhile, care must be taken with system vulnerabilities discovered under time synchronisation attacks. Delay, modification, denial of service and systematic spoofing attacks can result in deterioration of synchronisation accuracy. A transformer differential protection scheme was selected as an example to evaluate, theoretically and experimentally, the effect of inadequate time synchronisation on operating characteristics. The transfer latency of various process bus data including PTP, SV and Generic Object Oriented Substation Event (GOOSE) is studied using in-service Ethernet switches supporting seamless redundancy protocols. The obtained data transfer characteristics can be used to enhance the accuracy of latency estimation. Using the hardware testbed with 'live' substation equipment discovers factors that often struggle to be found in simulation and analytical studies. The findings of this research can be used as a performance reference which is valuable for various stakeholders including the standard board, power utilities, manufacturers and other academic researchers.
Date of Award31 Aug 2021
Original languageEnglish
Awarding Institution
  • The University of Manchester
SupervisorZhongdong Wang (Supervisor) & Qiang Liu (Supervisor)


  • IEEE 1588
  • IEC 61850
  • Precision Time Protocol
  • Substation automation systems
  • Protection, automation and control
  • Digital substation

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