Sampled Values and IEC 61850-9-2 LE: What is it?

The other day I received the following email:

Dear Mr. Karlheinz Schwarz,
I am sorry to disturb you. My name is XXX and I am a researcher from YYY. I would like to ask some questions to you regarding the standard IEC 61850-9-2LE.

1) May I know the status of IEC 61850-9-2LE? Is the standard will be obsolete or remain as it this?

2) Can I get some explanations from you about the differences between IEC 61850-9-2, IEC 61850-9-2LE and IEC 61869-9?

I really appreciate your kindness and time to answer my questions above.
Thank you & best regards,

-------------------------------

I have a very good friend that I asked to answer for me. Her is his answer:

Dear Karlheinz, 

Sure I can do my best for that.

Thanks for this opportunity.

Dear XXX, please see my attempt to answer.

Your questions are our everyday’s questions, and my answers need to be taken with “common sense”, reasonability and not as law, where somebody is right and somebody is wrong.

This is the best I can say.

The IEC 61850-9-2 Light Edition (LE)  is NOT a standard.  It is an UCA profile; a sort of gentlemen agreement (followed by everybody so far), where in principle the dataset carried by the SV Message (Sampled Values message) is fixed to 4 voltages and 4 currents.

The sampling frequency is 80 samples per period (4000 Hz for 50 Hz systems and 4800 Hz for 60 Hz systems).

The length of the SV message is fixed (in terms of bytes)

The quality string has one “extra bit” (the 14th bit, for derived or measured of the analog quantity) compared with a “normal quality string” of IEC 61850 and also IEC 61869 series, of 13 bits.

The time synchronization is 1-PPS

There is formally no support for PTP time synch (typical of “Edition 2” of IEC 61850 standard. LE is “edition 1”)

There is formally no support for “SIMULATION” mechanism (typical od “Edition 2 “ of IEC 61850 standard; LE is “edition 1”)

And many others.

TO MY EXPERIENCE:

It is commonly understood (and you have to make sure it is commonly understood also by the people working in your projects: suppliers, consultants, utility engineers etc) that:

- 9-2 LE supports Simulation mechanisms

- 9-2 LE supports PTP as time synch (be careful that PTP is actually IEC 61850-9-3: 2016 )

Even if formally this is not strictly in line with the UCA specification for “LE”.

So, IEC 61850-9-2LE (written by UCA working group) is a profile of IEC 61850-9-2 (written by the IEC committee TC 57)

And today it is the only “standard” that is implemented and in service for process bus applications.

IEC 61869-9 (and also -6 and also soon the -13) are parts of the IEC 61869 series, written by the IEC committee TC 38 (Instrument Transformer). 

So they have to do with the Merging Units, they are also profiles somehow, and also many other requirements, that you need to fulfill if you want to have a Merging Unit according to IEC standards.

To my opinion, no matter what IEC 61850 says in general, if you do a Merging Unit and follow IEC, you should follow IEC 61869 series.

In principle, the IEC 6185069-9 standards are often associated to:

• “Dynamic” dataset. This means that not only 4 U and 4 I will be transmitted. I can transmit just  one voltage, or 25 currents, or 6 voltages and 3 currents.. This is done from SCL.
• Sampling frequency of 4800 Hz, no matter the power system frequency (50 Hz or 60 Hz).
• PTP time synchronization (for MU)
• 2 samples per SV message (so called ASDU). “LE” has only one sample per message (one ASDU per message)

But it is of course much more than that.

What about protection relays/protection functions?

TC 95 is responsible for protection functions in IEC.

In principle it  is TC 95 / MT 4 (Maintenance Team 4) that takes care of functional standards for protection functions (IEC 60255-121:2014 for distance protection for example). Other maintenance teams take care of protection related standards like EMC etc.

Recently TC 95 has started a new working group (WG 2) that considers IEC 61850 for protection applications. A Technical Report is on its way and parts of that technical report will be implemented in the so called IEC 60255-1xx series, for protection relays.

But this is not ready yet and all of this needs to be considered with extreme care and communication among all the involved parts in a project.

I work as well as consultant for IEC 61850 applications in relay protection. Mainly for TSOs, since many years. Please have a look at this paper, written by many of us active in TC 95 / WG2. I think it will help you to better understand.

https://www.researchgate.net/publication/334050781_Standardisation_Challenges_for_Digital_Inputs_and_Outputs_of_Protection_Functions_in_IEC_60255_series

If you are interested in what TC 95 / WG2 does, you are more than welcome to contact me and I’ll help you in joining “our” activities.

For your understanding, there is a high dialog between TC 95, TC 38 and TC 17 (circuit breakers) for making the use of IEC 61850 more interoperable not only at “data level” but also at “functional level”, at least for protection applications.

For metering or power quality applications, for example, I don’t know what to say.

I hope this helps you.

Karlheinz, your extra comments are always welcome.

My best regards

Andrea Bonetti

Just passed

 Fachtagung Schutz- und Leittechnik 2020 , Berlin, 18-19 February 2020

NEW FORMAT!  Megger Magazine: ELECTRICAL TESTER
White Paper - Testing ROCOF and IEC 60255-181 Standard

Article - IEC 61850 GOOSE interoperability
IEEE 2018- Paper on IEC 61850 substation maintenance
MATPOST 2019 Lyon FR – Paper on IEC 61850 and Automatic Fault Disturbance Analysis

First time in industry! long duration End to End testing without use of any computer!

Mr. Andrea Bonetti MSEE
Senior Application Specialist Relay Protection and IEC 61850
Active member of IEC TC 95 / MT 4 ”Measuring relays and protection equipment” since 2006.
Megger Sweden AB

andrea.bonetti@megger.com
Rinkebyvägen 19, SE-182 36 Danderyd (Stockholm)
Sweden

IEC 61850 Sampled Values and GOOSE Messages Reduce Complexity and Cost

Synaptec Ltd (a spin-out technology company from the University of Strathclyde, UK) developed a distributed electrical sensing technology platform using IEC 61850. The approach allows measured values from up to 50 current transformers to be acquired passively using a single optical fibre core over a distance of up to 50 km. These measured values can then be utilised as part of centralised PAC schemes, or communicated to traditional PAC devices for analysis via IEC 61850-9-2 / 61869-9. By centralising current measurements, this method eliminates the need of having multiple protection relays at each line ends, complex time synchronisation systems at measurement points, and complex telecommunications equipment among the distributed PAC devices.

Click HERE for downloading the 12 page paper (Differential protection of multi-ended transmission circuits using passive distributed current sensors) describing the application and approach to solve a very crucial challenge.

Another paper (Implementation of centralised, numerical busbar protection using distributed photonic current sensors) describes the design and testing of the first centralised busbar protection scheme that makes use of distributed photonic current sensors and IEC 61850. By utilising distributed, passive sensors which are interrogated purely using standard optical fibre, the requirement for active units in the substation yard is completely eliminated. Additionally, the use of copper wiring from CTs to measurement units may be eliminated. The scheme, designed and built for Statnett by Synaptec, will be installed and trialled at Statnett’s Furuset R&D substation near Oslo, Norway. A prototype centralised busbar protection algorithm, validated with the University of Strathclyde, will run on the central merger unit to prove the principle of centralised busbar protection using a single active IED.

Click HERE for downloading the paper.

Click HERE for the Synaptec news (Norwegian TSO Statnett innovates with Synaptec technologies):

With one system able to instrument 50 locations synchronously, 6 busbar feeders will be independently and simultaneously protected by one system, with capacity to spare for novel temperature and vibration monitoring of nearby HV assets, such as transformers.

The development and the applications show that the standard series IEC 61850 has all the "tools" helping to keep the power flowing and the grass green - at all voltage levels.

New Merging Unit Development Kit

A new Merging Unit Development Kit based on the NovTech IoT Smart Grid Platform with Intel Cyclone V SoC Core is available for your next project.
Utility companies are adapting their infrastructures to support bidirectional energy flow to handle the emergence of DER (Distributed Energy Resources) via microgrids, photovoltaic panels, and local energy storage. As distributed energy generation increases, new intelligence of sensors, measurement and protection equipment will be required to process data at the edge. Also with the increase in variable DER, it is more challenging for substations to deliver sinusoidal and predictable steady-state voltage and current. Utility companies rely on substation metering of secondary voltage (VT) and current transformer (CT) circuits to detect performance issues and to provide vital information in real time to distributed digital protection nodes.

To satisfy this need, SystemCORP and Intel developed an IEC 61850-9-2LE compliant merging unit solution in form of a demonstrator/development platform.

This development kit consists of 6 parts:

1. NovTech IoT Octopus Smart Grid IoT Platform
2. SystemCORP VT/CT Interface board
3. SystemCORP IEC 61850-9-2LE Sample Value software stack (PIS-11) on ARM Cortex A9 core 1
4. SystemCORP IEC standard 61850 server/client software stack (PIS-10) on ARM Cortex A9 core 2 (optional)
5. Flexibilis embedded FPGA analogue front-end IP core
6. Flexibilis Ethernet PRP/HSR FPGA IP core (optional) 

Click HERE for more information.

NEW HW: IEC 61850-9-2 LE Sampled Value Publisher

The SystemCorp "IEC 61850-9-2 LE Sampled Value Publisher" is a hardware platform for specific sampled value publisher applications for the Smart Grid IoT Platform from Novtech using the Altera (now part of Intel) dual core ARM/FPGA Cyclone V SoC.
This Smart Grid IoT Platform provides eight high precision analogue inputs. The A/D converter is directly controlled by the FPGA producing the sampling rate required for the SV publisher,   which is implemented in one ARM core.
The Sampled Values are published at a rate of 4000 frames per second for a grid frequency of 50Hz and 4800 frames per second for 60 Hz.
An eight channel VT/CT interface module is also available from SystemCORP Embedded technology allowing a direct connection of the Smart Grid IoT Platform to 110 V VTs and 5 A CTs.





Click HERE for downloading a two page description and additional information [pdf, 390 KB].

New Merging Unit from Alstom according to 9-2LE

Alstom Grid is offering a new Merging Unit according to 9-2LE that supports the integration of conventional current and voltage samples into a all digital substation:

Click HERE to download a brochure on the Merging Unit.

According to the UCAIUG Users Group there are now 10 Merging Units certified by the Users Group.

Market Trend: IEC 61850-9-2 Sampled Values accepted

Omicron has published a paper on the benefits and acceptance of the IEC 61850-9-2 sampled values:

English (Page 47-49)

Deutsch (Page 43-45)

By Dr Fred Steinhauser:
Technology of the future: Sampled Values provide many benefits for the power systems of tomorrow

Abstracts: “IEC 61850 defines several kinds of communication mechanisms. The Client/Server communication for SCADA and the GOOSE protocol for peer-to-peer status messaging have been widely adopted in a quite short time. Now, after years of experience with these new protocols, also the application of Sampled Values has become a common topic.”

IEC 61869-6: The IEC 61850 Interface for Instrument Transformers

IEC TC 38 has published the new Committee Draft (CD) for the Digital interface for instrument transformers (38/418/CD):

IEC 61869: Instrument Transformers -
Part 9: Digital interface for instrument transformers

This standard defines a method for digital communications of instrument transformer
measurements. It is based on the IEC 61850 series of standards, IEC 60044-8 and the UCA International User Group document Implementation Guideline for Digital Interface to Instrument Transformers Using IEC 61850-9-2 (known as 9-2LE). It includes additional improvements including IEC 61588 network based time synchronization, and frequency response requirements.

This new standard will be part a product family standard for instrument transformers. It provides an application of the horizontal standard series IEC 61850, which details layered substation communication architecture in the world of instrument transformers.
By providing tutorial material such as examples and explanations, it also gives an access for instrument transformer, protective relay and meter experts to concepts and methods applied in the IEC 61850 series.

An overview about the standard series 61869 is shown in the next picture:

• Part 9 Replaces IEC 60044-8 digital solution.
• Provides a product standard for instrument transformers with a digital interface according to 61850; similar to what IEC 62271-3 is doing for switchgear.
• Includes backward compatibility for the UCA International User Group Implementation Guideline for Digital Interface to Instrument Transformers Using IEC 61850-9-2.
• Uses IEC 61588-Ed2 for time synchronization, with an option for 1PPS.

The CD ballot closes 2011-11-04.

Contact your national IEC TC 38 or TC 57 committee to get a copy of the CD.