computer science

IEC/IEEE 61850-9-3

IEC/IEEE 61850-9-3 is a computer science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand IEC/IEEE 61850-9-3 rather than just read about it. In short: 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. It supports precise time stamping of voltage and current measurement for differential protection, wide area monitoring and protection, busbar protection and event recording.

Key takeaways

IEC/IEEE 61850-9-3 belongs to computer science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect IEC/IEEE 61850-9-3 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of IEC/IEEE 61850-9-3 from memory before moving on to harder problems.

Reference excerpt

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. It supports precise time stamping of voltage and current measurement for differential protection, wide area monitoring and protection, busbar protection and event recording. It can be used to ensure deterministic operation of critical functions in the automation system. 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:

uses the PTP timescale based on TAI International Atomic Time, also delivers UTC Coordinated Universal Time communicates on Layer 2 over Ethernet (IEEE 802.3) links, either in a local area network or in a wide area network (Metro-Ethernet) measures the link delay by peer-to-peer (Pdelay) message exchange transmits the clock correction indifferently in 1-step (preferred) or in 2-step operates with the default best master clock algorithm, performed by master and by slave clocks

Performance IEC/IEEE 61850-9-3 aims at an accuracy of better than 1 μs after crossing 15 bridges with transparent clocks. It assumes that all network elements (bridges, routers, media converters, links) support PTP with a given performance:

Grandmaster (GC): 250 ns maximum inaccuracy Transparent Clocks (TC): 50 ns maximum inaccuracy Boundary Clocks (BC): 200 ns maximum inaccuracy Media Converters: 50 ns maximum jitter and 25 ns maximum asymmetry Link asymmetry: 25 ns maximum asymmetry 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. 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:

domainNumber: 0 (default), 93 (when conflict exist with another PTP time distribution) Announce interval: 1 s (fixed) Sync interval: 1 s (fixed) Pdelay interval: 1 s (fixed) Announce receipt time-out: 3 s (fixed) priority1: 255 for slave-only priority2: 255 for slave-only transparent clock primary syntonization domain: 0 (default)

Additions to IEEE Std 1588 All clocks can be doubly attached using the IEC 62439-3 protocol (PRP "Parallel Redundancy Protocol" or HSR "High-availability Seamless Redundancy"). Several master clocks can be active at the same time; the slave selects the best master. Time-outs ensure that the clocks can detect the loss of PTP messages also on the unused path. Identification of the peer node to check the topology of the network and ensure that all elements support the protocol. In network using store-and-forward media converters, the master appends a padding to Sync messages to ensure that Sync and Pdelay_Req/Pdelay_Resp messages have the same size (this will specified in IEEE 1588:2017) Network management by SNMP according to IEC 62439-3 Annex E or by IEC 61850 consider the extension

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.

References

External links IEC 61588:2009 Precision clock synchronization protocol for networked measurement and control systems IEC/IEEE 61850-9-3, Communication networks and systems for power utility automation – Part 9-3: Precision time protocol profile for power utility automation IEC TR 61850-90-4:2013 Communication networks and systems for power utility automation - Part 90-4: Network engineering guidelines Tutorial on HSR Archived 2017-02-05 at the Wayback Machine Tutorial on Parallel Redundancy Protocol (PRP) Archived 2017-02-04 at the Wayback Machine Tutorial on the fault-tolerant precision time protocol profiles in IEC 62439-3 IEC 62439-3 Tissues (Technical issues) database for IEC 62439-3 Archived 2018-01-14 at the Wayback Machine IEC 61850-9-3 Tissues (Technical issues) database for IEC/IEEE 61850-9-3

Illustrations

Worked examples

Example 1 — a first encounter with IEC/IEEE 61850-9-3

Start with the simplest possible case. Write down what IEC/IEEE 61850-9-3 claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In computer science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to IEC/IEEE 61850-9-3 before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about IEC/IEEE 61850-9-3 ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of IEC/IEEE 61850-9-3

In research: IEC/IEEE 61850-9-3 appears in computer science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses IEC/IEEE 61850-9-3 in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: IEC/IEEE 61850-9-3 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Network protocols, Networking standards, so understanding it makes those chapters shorter.
In everyday life: Look for IEC/IEEE 61850-9-3 outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study IEC/IEEE 61850-9-3 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what IEC/IEEE 61850-9-3 means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain IEC/IEEE 61850-9-3 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is IEC/IEEE 61850-9-3 in simple terms?

Why does IEC/IEEE 61850-9-3 matter?

Because it connects several computer science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study IEC/IEEE 61850-9-3?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on IEC/IEEE 61850-9-3.