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IEC 61850

Communication networks and systems in substations and beyond

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General Q&A

Questions and answers are in historical order. In most cases more comprehensive answers have been given during our training courses.

Last updated: 2007-06-18

- Question Answer
1
  • What is the current status of the 14 parts of IEC 61850?
  • (2004)
  • 13 of 14 parts are already published as International Standard (IS), the last part (Part 10) is under FDIS ballot (Final Draft International Standard). A more up to date table provides a list of links to the official status (listed at the IEC website) of each part.

    See: http://www.nettedautomation.com/news/n_72.html

    Some of these parts (IEC 61850-7-4 and IEC 61850-7-3) will be extended in the future to cover additional application domain.

    2 Transport profiles for IEC 61850. For transmission in real time why not use UDP/IP?
    (2004)

    Real-time applications are mainly required for GOOSE and Sampled Value exchange (SV). The standard transport profile for these real-time applications is just Ethernet/Ethertype and IEC 61850 specific messages defined in IEC 61850-8-1 for GOOSE and IEC 61850-9-2 for SV.
    TCP/IP is only used for all the client/server information exchange like GetDataValues or Reporting.

    3 Interface for voltage and current transformers
    (2004)

    The part IEC 61850-9-2 (Specific communication service mapping (SCSM) - Sampled values over ISO/IEC 8802-3) defines the interface for sensors. The UCA International Users Group provides a profile of this part for immediate use of the standard. Products see here.

    4 Purchase standards documents
    (2004)

    Standards are sold by IEC Central Office in Geneva and by some national standardization organizations like DIN in Germany. The Users Group does not sell standards!

    5 What is the IEC 61850 status as a "real" protocol, has it been used in real installa-tions?
    (2004-05)
    Depending on what people understand is a “real” protocol the answers may vary.

    The crucial parts of IEC 61850 have been published in 2003. So, it will take some time before we see a wide variety of devices. The expectation is that by end of 2004 vendors involved in the standardization have their key devices and systems equipped with IEC 61850 compliant software.

    15 vendors demonstrate their products at the Cigré exhibition in Paris in September 2004.

    Since the standard is quite new the market could not yet pro-vide as many devices compliant to IEC 61850 as it provides de-vices for other solutions, e.g., DNP3 (which is available for many years ).

    6 Are there any possible "competitors" to IEC 61850 in the near future?
    (2004-05)

    Depending on what people understand is a “competitor” to IEC 61850 the answers may vary.

    There is no other series of standards that covers the areas:

    • comprehensive information models (7-4 and 7-3) (only in IEC 61850 !!)
    • comprehensive services (almost only in IEC 61850 !!
    • GOOSE (only in IEC 61850 !!)
    • sampled value exchange (only in IEC 61850 !!)
    • configuration language (only in IEC 61850 !!)

    The answer is generally: There is no competitor for the entire set of parts of IEC 61850. UCA2 is not a competitor by definition – it is a technical report only and it has been superseded by IEC 61850.

    Other specs like IEC 60870-5-10x or DNP3 cover just a very small part of the possibilities of IEC 61850.

    7 What is IEC 61850 providing additionally, compared with a theoretical protocol that would include the sum of functionality of IEC 870-5-104 and IEC 870-5-103 ?
    (2004-05)
    A lot!
    • comprehensive information models (7-4 and 7-3)
    • services (for Data Set, Reporting, Logging, …))
    • GOOSE (only in IEC 61850 !!)
    • sampled value exchange (only in IEC 61850 !!)
    • configuration language

    A comprehensive comparison of the solutions can be downloaded from:

    http://www.nettedautomation.com/news/n_51.html

    8 Is there any manufacture device with IEC61850? Are manufactures, in general, interested in working with this protocol? And electrical companies?
    (2004-05)
    Oh yes. No question at all.

    See demo at the Cigré exhibition in Paris in September 2004.

    The request for IEC 61850 is a key in today’s tenders.

    9 How could a substation communicate with the SCADA and which protocol we can use?
    (2004-05)
    The IEC 61850 could – from a technical viewpoint – be used for SCADA applications. The use of IEC 61850 for the communica-tion between a substation and a control center depends on the philosophy of a utility.

    It is very likely that in the long-term IEC 61850 will be used as the seamless solution in the whole chain of the electric power system: from the generation over the transmission and distribu-tion to the (non residential) customer interface.

    IEC 61850 has all crucial services and definitions for SCADA in-formation exchange. The information models of IEC 61850 are very flexible in so far that they can easily be extended for any other application domain.

    By the way, substations are a major source of information used for SCADA. It is of a great benefit to use the process related in-formation (statuses and measurements) already made available by IEC 61850 and communicate them outside the substation.

    10 What IEDs are presently using this stan-dard?
    (2004-10)

    The standard has been published mainly in 2003 and 2004.

    At this time (Oct. 20004) there are many devices for protection, control, master applications, merging units, and general pur-pose applications available – mainly in the context of substations. Details to be discussed in the Seminar.

    The UCA International Usersgroup maintains a list of devices:

    Visit the www.ucausersgroup.org

    The Forum provides a Product List; see also the CD ROM for the Seminar in Chicago (Oct 2004):

    <<SUBCNF30Aug2004.pdf>>

    The standard has impacts on several aspects of a SYSTEM. It takes some time before hundreds of devices are available. It is not an issue of complexity! The standard is very comprehensive – you will learn this during the class.

    11 What are the advantages of using such a standard?
    (2004-10)
    Manifold – note it is not just another “DNP” or “MODBUS” … The key advantage/benefit:

    COST REDUCTION through

    • standard Information models, data management, …
    • applying standard technology like Ethernet TCP/IP, Web technologies, …
    • independency of today’s HW and SW
    • ONE solution for many power system applications
    • long-term stability

    Prevent

    • installing 10 or 20 Mega Byte of program code in IEDs for real time communication by “next generation Internet freaks”

    To name just a few. You will see more.

    12 What are the main differences between IEC61850 and UCA2.0?
    (2004-10)
    IEC 61850 is THE standard – UCA2.0 is a “historic landmark” on the way to IEC 61850.

    For details see the following document on the CD ROM for the Seminar in Chicago (Oct 2004):

    <<Comparison-UCA-61850_R1-2_2004-09-08.pdf>>

    13 When can we expect that the majority of products will be 61850 compliant?
    (2004-10)
    Which products? It depends on the type of devices you are looking for.

    Details: see seminar

    14 In talking to a number of North American vendor reps, there still seems to be a great amount of skepticism on the useful-ness and therefore the adoption of 61850. What is your expectation on the accep-tance of this standard by the market both in Europe and North America?
    (2004-10)

    Many people have the opinion that the standard is very complex – more complex than …

    People tend to name something “complex” that they do not really understand. This is an issue with regard to IEC 61850. The SERIES of standards in IEC 61850 covers many areas (that are not touched by solutions like DNP3). It is crucial to under-stand the basic concepts and the comprehensiveness of IEC 61850!!

    The key issue is: what are people looking for? Are they expect-ing that IEC 61850 is just another DNP3-like specification?

    It is obvious that the market is ready for such a new technology – but there seems to be little investment in automation systems in Europe and in North America.

    The market penetration will pick up once the market picks up.

    The demonstration of IEC 61850 compliant devices and systems during the CIGRÉ exhibition in Paris in September 2004 and the many discussions we had with vendors and users have learned this lesion:

    • the market is looking for a long term standard solution solving the problems of future automation/monitoring systems
    • many experts coming by were surprised that this stan-dard is available !

    We are still at the beginning of the application of this new (or let’s say extended) possibilities in the automation and monitor-ing the power system.

    Many devices available right now would not help a lot – there are not enough experts trained to make use of the new possibilities.

    It takes some time!

    15 What type of problems could we expect in the first few years of working with 61850 compliant equipment? (i.e. what type of growing pains can we expect and what should we be watching out for?)
    (2004-10)
    That depends highly on what you are using. One thing is sure: People have to cope with the many networking aspect (Ethernet, switches, routers, VPN, security, “high speed”). We all need to gain experience with that new technology.

    Rome was not build in one day – so will be substations not be build over night with devices supporting everything of IEC 61850.

    Most of these networking related issues are independent of IEC 61850! Even MODBUS and DNP use this new networking tech-nology and – of course the new web technologies. So: There is nothing real special with IEC 61850 – this is the general trend!

    One could also ask the question: What type of problems could we expect if (the single standard) IEC 61850 compliant equip-ments are not used?

    You see, there is a tendency in the software industry to use more and more simple XML-tools to easily write XML-based communications software!! Almost every programmer is an in-dependent expert to standardize his/her OWN communication solution based on XML, HTTP, SOAP, Java, … This results in thousands of new communication protocols and information specification methods/solutions!!

    Having a standard may not help – but having no stan-dard hurts!

    16 How can the ethernet networks be de-signed to optimize the network speed and performance versus the cost of implemen-tation? (i.e. breakdown of the network into efficient subnets)
    (2004-10)
    To be discussed and answered during the class.

    The application of priority tagging keeps the low priority traffic (reading, reporting, logging) away from the high priority infor-mation (GOOSE and SV).

    A good network design is required. Experience over the next years is a key issue.

    17 What type of skills will be required by a project team to effectively develop 61850 compliant systems?
    (2004-10)
    This depends mainly on how much of the various aspects of the standard you want to implement on your own:

    If you want to develop your own (optimized) Ethernet chip, you need good expertise in chip design and …

    If you want to develop your own TCP/IP stack, you need …

    If you want to develop your own upper layer stack, you need …

    If you want to use available HW/SW, then you many need the skills to INTEGRATE and USE these “componenets”

    Make sure – in any case – to get a good SW architecture for the integration of the IEC 61850 related SW into your application SW. The interface between these two is crucial. How does the application “talk” with the communication software? Merge ap-plication SW and communication SW into one box?

    Of course you need general and specific network expertise (see above).

    It is also very crucial to start early to architect the new ap-proach of system and device engineering based on the informa-tion models and the various aspects of the substation configuration language.

    18 Can automation functions be implemented based on IEC 61131?
    (2004-05)
    The standard IEC 61131-3 could be used to describe the pro-grammable logic. The programs can be downloaded by IEC 61850-7-2 file services.
    19 Is there any publicly IEC 61850 server with a sample IED implementation available (say, an educational unit)?
    (2004-05)
    Please find below the access information for Servers on the Internet:

    The MMS servers are at:

    SEL 421: 204.254.125.150

    Areva M871: 204.254.125.149

    GE UR F60: 204.254.125.148

    The SEL 421 is not connected right now but will again soon.

    I think that these are UCA2 devices right now. We expect 61850 updates from these vendors soon but I don't have an exact date.

    We did not test them.

    20 What is the Model Maintenance process of IEC 61850 models?
    (2004-08)
    There are the following aspects of maintenance:

    1. The correction of the existing documents IEC 61850-7-4:2003 and IEC 61850-7-3:2003. This is an issue that will be handled in the technical corrigenda of these parts (tech-nical corrigenda could be expected end of 2004 or begin-ning of 2005, the UCA International usersgroup will publish a list of such issues and recommend how to solve them).

    The IEC TC 57 WG 10 is responsible for the publication of the corrigenda.

    2. Extensions of the “core models” of IEC 61850 for common use, e.g.,

    a. the definition of power quality monitoring mod-els

    b. the statistical (MIN, MAX, …)

    c. historical statistical (hourly MIN, daily MIN, …)

    These common definitions will be added as amendments to the 2003-versions of the models. Later they will be inte-grated into the next version of these standards.

    The IEC TC 57 WG 10 is responsible for the publication of the amendments.

    3. Several other IEC Working Groups are specifying domain-specific model extensions, e.g., for wind power plants, hy-dro power plants, decentralized energy resources (DER), …

    These groups closely cooperate with IEC TC 57 WG 10.

    21 What is the most effective link with CIM Model?
    (2004-08)
    The CIM model (IEC 61970) and IEC 61850 deal with two dif-ferent aspects of the electric power system:

    1. IEC 61970 – control center view of the system (of lines, transformers, switches, measurements, …)

    2. IEC 61850 – substation internal automation

    A lot of information (measurements, statuses, single-line dia-grams, etc.) of the substation are viewed from these two stand-points. It is mainly the substation configuration (IEC 61850-6) of this information that has to be based on the CIM-Document (“the big view”) for that substation.

    Secondly, the names of the real measurements and status in-formation of a substation have to be mapped to the names (paths) of the control center view (derived from the CIM-Document).

    More details see: the presentation of the Configuration in the Seminar.

    22 How about the interoperability tests around 61850?
    (2004-08)
    One key issue is the conformance tests for IEC 61850. These are defined by the market participants under the umbrella of the UCA International Usersgroup. The corresponding rules and guides are developed according to the part 10 of the standard IEC 61850. Part 10 has been accepted as FDIS. The standard part 10 will be available by end of 2004 or beginning 2005.

    Interoperability test are organized by several groups as required by the market (especially in the context of multi-vendor substa-tions).

    Several interoperability tests have been run for the GOOSE and sampled value exchange.

    23 What is the ROI of applying IEC 61850?
    (2004-08)
    See presentations during the seminar.
    24 What is the Migration process to IEC 61850?
    (2004-08)
    See presentations during the seminar.
    25 Evolution of 61850 and other standardization process (EPRI UCA2 ?, ...)
    (2004-08)
    The evolution of IEC 61850 has started with the many domain-specific extensions of the information models. There are also extensions for the mappings of the ACSI (services) to web ser-vices (underway in IEC TC 88 PT 25 – Wind power plant exten-sions for IEC 61850).

    UCA2 never was a standard (just an IEEE Technical Report). There is by definition and decision no evolution process for UCA2. One could say that the evolution of UCA2 resulted in the standard series IEC 61850 – somehow. It was decided by IEC and IEEE in 1998 that the maintenance of UCA2 is the standard IEC 61850.

    But: the name “UCA” is still on the market. The UCA Interna-tional Usersgroup uses this name as an abbreviation of a suite of specifications for the utility industry: IEC 61850, TASE.2 (ICCP, IEC 60870-6 TASE.2), CIM, …

    26 IEC 61850 and UCA2.0. Can you provide some of the differences? Can an IED talk-ing UCA be integrated in a 61850 net-work?
    (2004-08)
    The main differences are:

    1. more comprehensive information models (7-4 and 7-3) in IEC 61850; more flexible than GOMSFE

    2. GOOSE (only in IEC 61850 !!); UCA2 GOOSE is the same as the IEC 61850 GSSE (for backward compatibil-ity reasons)

    3. sampled value exchange (only in IEC 61850 !!)

    4. configuration language (only in IEC 61850 !!)

    5. use of Ethertype (priority tagging of messages) only in IEC 61850

    The integration of IEDs talking UCA into networks with IEC 61850 is very limited. The reasons are:

    1. UCA2 uses MMS Version 1 (1991)

    2. IEC 61850 uses version 2 (2003) – new UTC time stamp, 64 char for object names, …

    Clients may talk easily to UCA2 servers and IEC 61850 servers. The peer-to-peer communication UCA2 GOOSE and IEC 61850 GSSE can interoperate (but the question is if GSSE will be used a lot in the future – IEC GOOSE is much more flexible).

    Most vendors will have IEC 61850 compliant devices only.

    27 Masters for 61850. Many manufacturers claim to have IEDs for 61850. However, I do not know any manufacturer of a PC program that can read data from 61850 devices.
    (2004-08)
    The browsers of SISCO, LiveData and Tamarack provide access from PCs to IEC 61850 compliant IEDs.

    Many other vendors like ABB, AREVA, GE, Siemens have reported that they have master stations available.

    Contact the vendors directly.

    28 Goose. How can one be sure that the Goose messages reach the target?
    (2004-08)
    The GOOSE messages are usually automatically retransmitted in short intervals (for some time, the interval then increases).

    The first automatic retransmission is much earlier than waiting for an acknowledgement to the first message and then – if there is after a certain time no acknowledgement – retransmits the first message! An “acknowledgement” will, e.g., be received by the new report (or GOOSE message) of the state change.

    More details will be presented during the seminar.

    29 What does OPTIONAL (O) in an information models (like the data of a LN) mean?
    (2007-06)
    Part IEC 61850-7-4 defines: "M/O/C defines whether data, data sets, control blocks or services are mandatory (M) or optional (O) or conditional (C) for the instantiation of a specific Logical Node."

    The decision to use or not to use optional items can be made by the vendor of an IED, the system integrator or by the user. If the vendor decides not to provide an optional item, then the system integrator and user cannot request this item! In this case they have to accept the non-availability of the item.

    Some people have interpreted optional in the following way: the vendor has to provide also optional items, and the user can decide to use them or not.

    Many Q&A topics are available to attendees of our training courses ... the list is growing ... tap it by attending our courses.


    18.06.2007


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