Wednesday, August 28, 2019

Why Is It So Easy To Map IEC 61850 Signals to JSON Objects?

IEC 61850 defines Device Models for the exchange of information between any two or more entities. The Models are structured as unique branches of a tree.That means:

Each path from the Device (Root) to 
any node or leave of the trees is unique

The signals are composed of an access reference (LDName/LNName.DOI. ...) and the value that corresponds with the path.

Example of two leaves:
LDName/Tran1STMP1.Tmp.mag.f = 23.5 (Temperature value)
LDName/Tran1STMP1.Tmp.units.SIUnit = °C (Temperature engineering units)

These are key-value pairs that could easily map to JSON Objects:

"LDName/Tran1STMP1.Tmp.mag.f " : "23.5"
"LDName/Tran1STMP1.Tmp.units.SIUnit" : °C

These JSON objects are

  • Light-weight
  • Language independent
  • Easy to process with Python, ...
  • Text based and human readable 
  • JSON Schemas could support automatic (syntax and semantic) checks
  • JSON is supported by many controllers
The controller of our PV inverter from Fronius has an http/JSON interface. The following request (lines 1-3) returns many common inverter data (line 21ff):



Lesson learned: Controller in inverter could easily provide an http/JSON interface.

The Device Model is a virtual model that could be configured using the SCL (System Configuration Language, IEC 61850-6). The Device Model is implemented in an IED and could be accessed to get the self-description, read, write, send/receive reports, publish/subscribe, ...

An IEC 61850 Server hosted by an IED could easily map the model to JSON objects that may be communicated with MQTT, HTTP, ...

The mapping to JSON is quite easy. It could be implemented by a simple automatic process that parses the model (SCL/XML), searches for the paths and concatenates the names from the root to the leaves to get the reference! AND: the mapping preserves the semantic - the meaning represented by the path name.

The mappings of IEC 61850 Models to IEC 60870-5-104, DNP3 or Modbus would result in messages that have lost the semantic of the signals. These solutions have mainly numbers as reference - these numbers have no meaning in the communication.

FDIS Ballot for Amendment 1 for IEC 61850-7-2, 7-3 and 7-4 Edition 2 Approved

The ballot of the three amendments (Amendment 1 for IEC 61850-7-2, 7-3 and 7-4 Edition 2) passed the FDIS process. All three amendments have been approved by 100 %.

The next step will be the IS publication of the three amendments.

It is likely that there will be a consolidated version of each of the three parts - means: the amendment is merged into the edition 2 versions and become edition 2.1.

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.

Monday, August 19, 2019

Tissue Process for IEC 61850-8-2 open for posting Tissues


Please note that the Tissue Database is now open for part IEC 61850-8-2:

Communication networks and systems for power utility automation –
Part 8-2: Specific communication service mapping (SCSM) – Mapping to Extensible Messaging Presence Protocol (XMPP)

http://tissue.iec61850.com/part/52

Friday, August 16, 2019

VDMA-Leitfaden: "Interoperabilität durch standardisierte Merkmale“

Der VDMA (Verband Deutscher Maschinen- und Anlagenbau) hat diese Woche einen sehr interessanten 70-seitigen Leitfaden zu Industrie 4.0 veröffentlicht!

Interoperabilität durch
standardisierte Merkmale
Leitfaden für Industrie 4.0

HIER klicken für mehr Information und den Kontakt.

„Der Leitfaden „Interoperabilität durch standardisierte Merkmale“ beschreibt, wie Signale und
Werte zwischen Fertigungseinheiten ausgetauscht werden und folgt so der Industrie 4.0-Idee.
Das Schlüsselwort ist "Standardisierung". Produkte, Einzelteile Baugruppen oder
Anlagenelemente sind durch Merkmale beschrieben, die in einem Format übertragen werden.
Die Merkmalbeschreibung sowie das Übertragungsformat liegen in standardisierter Form vor
und bilden eine gemeinsame "Sprache". Diese Sprache bildet die Basis dafür, dass empfangende
Systeme die Daten korrekt verstehen, ...“

Der Leitfaden hat natürlich meine Neugierde und mein Interesse geweckt!

Die hier empfohlenen Maßnahmen und Vorgehensweisen gehen genau in die richtige Richtung ... sie setzen im Prinzip da auf, wo wir Anfang der 90er Jahre mit MAP 3.0 und den MMS-Companion-Standards aufgehört haben!

Seit 2005 haben wir zwei Normenreihen (IEC 61850 und IEC 61400-25), mit denen ein guter Teil der im Leitfaden vorgeschlagenen Methoden realisiert wurde und global angewendet wird – leider „nur“ im Bereich der elektrischen Energieversorgung (und hier anfangs zunächst im Hochspannungsbereich). Vor allen elektrischen Systemen mit mehr als 400 V haben die meisten Automatisierer ohnehin großen Respekt – und lassen die Finger von Automatisierungslösungen in diesem Bereich. Das hat sich heute schon vielfach als Fehler herausgestellt.

Die meisten Experten - auch aus dem Maschinen- und Anlagenbau - erwarten nicht, dass wir für die anfangs auf die elektrische Energieversorgung fokussierte Automatisierungswelt Lösungen definiert haben, die auch in vielen anderen Bereichen angewendet werden können!! Ja wirklich!

Es ist ja schon (fast) alles definiert und genormt worden – nur noch nicht von allen!!

Monday, August 12, 2019

IEC TC 57 Just Published the IEC 61850-90-11 on Logics

IEC TC 57 Just Published the 90 pages of the Draft Technical Report IEC 61850-90-11 (57/2129/DTR)

Communication networks and systems for power utility automation –
Part 90-11: Methodologies for modelling of logics for IEC 61850 based applications

Voting closes 2019-10-04

"This Technical Report of IEC 61850 describes the methodologies for the modelling of logics for IEC 61850 based applications. ... the technical report

  • Defines different application uses cases where all aspects to be considered are clearly identified.
  • Describes the functional requirements and the intended engineering process
  • Proposes a suitable solution in the context of IEC 61850 based on an investigation of the different possibilities to model the logic.
  • Describes the impact on various parts of IEC 61850"
If, when and how this Technical Report will impact implementations of tools and IEDs is quite open. I remember that we had heated debates on the question how to deal with (internal) logics already some 10 years ago.

If you are planning to apply IEC 61850 - please DO NOT wait until this part 90-11 offers stable definitions ... IEC 61850 (as it is defined today) has enough to get started! ;-)

Thursday, August 8, 2019

Crucial Vulnerabilities Exist in the VxWorks IPnet Stack

According to Security Week (reported the other day):

"In late July, IoT security firm Armis disclosed eleven vulnerabilities found by its researchers in the VxWorks real time operating system (RTOS). The flaws, six of which have been described as critical, can allow a remote attacker to take control of impacted systems.
Armis said the vulnerabilities exist in the VxWorks IPnet stack and they expose over 200 million mission-critical devices from around the world to attacks, including in the healthcare, manufacturing, cybersecurity, tech, and industrial automation sectors. ..."

Devices from several vendors might be impacted ...

Click HERE for the full report. There you find links to the vendor's recommendations ... You know what that could mean? One vendor notes: "Applying the update causes the device / module to go through a single restart cycle."


Monday, August 5, 2019

Beck IPC offers MQTT@CHIP in addition to IEC 61850 and other protocols

Beck IPC (Wetzlar, Germany, a subsidary of HMS) is known for their solutions on a single CHIP offering support for IEC 60870-5-104, IEC 61850, Modbus, CANBus, Profibus, Profinet, OPC UA, ... now offers MQTT@CHIP as an additional solution.



The MQTT can be configured on the WEB PLC like it is implemented for other protocols:



In the above example I have mapped a signal from an IEC 61850 Server the signal MMXU1.TotW.instMag.f to a MQTT message. This way you can tag the signal as a JSON Object!!

JSON Objekte:
{ „MMXU01.TotW.instMag.f“:  2325, „MMXU01.Hz.instMag.f“:  49.98 }

Message specification:



This way you can send MQTT messages with values from any other protocol or from the IEC 61850 client or server model. This way you can even map to/from GOOSE messages.

I have used the solution running on the IXXAT Smart Grid Gateway. The WEB PLC version 19.2 is required to run MQTT on the gateway.

Very well done!

IEC Draft TR 61850-90-9 - "IEC 61850 for Electrical Energy Storage Systems" Published

IEC TC 57 just published the 138 page IEC Draft TR 61850-90-9

IEC 61850 for Electrical Energy Storage Systems

57/2128/DTR
Voting closes 2019-09-27

This is one of the next crucial extensions for DER-Models of IEC 61850-7-420. This TR will be merged into the 7-420 later on.

The Introduction states: " ...This technical report is primarily based on the recommendation 5.7.4. “interface, control and standard data elements”, of the IEC white paper ”Electrical Energy Storage” published in December 2011 by the MSB. The recommendation proposes the necessity of a standardization of interfaces between storage and other grid elements, protocols for data exchange and control rules, and data elements for input, output and control information supplied by or to storage systems. ..."

Click HERE for the mentioned IEC White Paper.

"This technical report describes IEC 61850 information model for electrical energy storage systems (EESS). Therefore the report only focuses on storage functionality in the purpose of grid integration of such systems at the DER unit level. Higher level Interactions are already covered in IEC 61850-7-420. ... "

The draft defines more than 150 new Data Objects. Excerpt of the first 15 Data Objects:



The blue marked text refers to the Logical Node from which this Data Object is inherited.

This document refers to the standards IEC 61850-7-x and defines additional very crucial information for the configuration, control, monitoring of a battery system.
It is very crucial for the success of the DER models to get implementation and application experience with these very comprehensive and complex models.
Taking into account that the mentioned White Paper was already published in 2011, we learn a crucial lesson: It took a lot of time to get where we are today. And it will take years to get these definitions implemented and used in the power delivery systems. In the mean time you need to tap the experience of engineers that understand the possible use-cases that can harvest the benefits of applying these standards.

Thursday, July 18, 2019

VDE-Studie "Lösungsansatz für Zellulares Energiesystem"

In dem neuen Papier „Zellulares Energiesystem“ zeigt jetzt der Technologieverband VDE eine effiziente und konsensfähige Lösung für eine erfolgreiche Umsetzung der Energiewende: Die VDE-Experten empfehlen den Strom direkt dort zu verbrauchen, wo er erzeugt wird, nämlich auf lokaler und regionaler Versorgungsebene. Bei diesem „zellularen Ansatz“ erfolgt die Umsetzung der dezentralen Energieversorgung auf Basis zellularer Strukturen.

Hier zum kostenlosen Download der Studie clicken.

Die Studie verdient vollen Respekt! Der holistische Ansatz verbindet viele der bisher versprengten, wenig aufeinander abgestimmten Lösungen zu einem ganz Neuen (dem zellularen Ansatz). Herzlichen Glückwunsch!

Der zellulare Ansatz wirkt teilweise futuristisch ... man darf natürlich auch mal träumen! Konkrete Leitlinien für einen Teil der Bürger unserer Gesellschaft sind allerdings rar und insbesondere der Aspekt der „überlebensdienlichen“ Notwendigkeiten scheinen etwas unterbelichtet zu sein. So heißt es auf Seite 26 : „Der Inselnetzbetrieb im zellularen Energiesystem soll nur im Notfall eine Option sein. Im Normalfall sind der Verbundbetrieb und die Solidarität die Regel.“

Es müssen unbedingt „überlebensdienliche“ Lösungen in Form von kleinen (vorübergehend) autarken, kostengünstigen Systemen (beispielsweise PV-System mit ein paar kWp, einem Batteriewechselrichter und ein paar Batterien) implementiert werden, um im wirklich großen oder kleinen Notfall Überlebenschancen für viele – besonders für Schwache – zu bieten.

Hintergrund für diese Position:

Meine Frau benötigt 24/7 ununterbrochene nicht-invasive Beatmung durch zwei Geräte mit jeweils 4-h-Akku Notfallversorgung. Ein Gerät für den Tag und eines für die Nacht. Ein 10-stündiger Stromausfall würde wahrscheinlich ... unvorstellbar.

Beatmungsgeräte für invasive beziehungsweise nicht-invasive Beatmung sind zig-tausendfach im Einsatz! Manche gehen von mehreren 100.000 aus!

Auf der anderen Seite haben wir eine netzgekoppelte PV-Anlage mit knapp 10 kWp ... soweit so gut. Die nützt uns im Notfall nicht, weil sie nur mit dem öffentlichen Netz zusammen funktioniert.

Bei einem Netzsaufall würden unsere PV-Module nutzlos auf dem Dach liegen und sich „sonnen“ ohne einen Sonnenbrand zu bekommen ... sie würden allerdings weiter Schutz für nistende Tauben bieten.

Momentan überlegen wir, wie wir die Module im Notfall manuell auf einen Batterie-Wechselrichter umschalten könnten. Das würde helfen, einen Teil der für Notfälle benötigte Energie vom Dach zu ernsten ... der Salat und die Tomaten im Garten würden ohnehin auch ohne Strom wachsen. Wasser können wir per Handpumpe aus dem Rheingraben pumpen.

Wir alle sollten mal überlegen, wie wir diese oder eine ähnliche Notfalllösung unter die Leute bringen könnten ... das wäre zwar nicht netzdienlich – aber auf jeden Fall auch gemeinschaftsdienlich! Geladene Batterien und mobile Inverter könnten auch an die Nachbarn oder ... ausgeliehen werden.

In unserem Fall haben wir zwei Notstromaggregate, Benzinvorräte und ein paar Bleiakkus mit zugehörigen Invertern. Für den Notfall würde ich gerne einfach einen Teil der Module manuell auf einen Batteriewechselrichter (vielleicht 2 kWp) umschalten. Wenn das Netz wieder verfügbar ist, dann kann man wieder zurückschalten.

Noch eine kleine Nebenbemerkung zum Thema IEC 61850 auf Seite 38:

„Für die Kommunikation und das Datenmanagement im Prozessnetz haben sich in den letzten Jahren
u.a. die IKT-Standards IEC 60870 (Datenmodelle für Energiemanagement) und IEC 61850 (Kommunikation) etabliert.“

Hier wurden offensichtlich die beiden Normen verwechselt! IEC 61850 bietet Datenmodelle ... u.v.a. mehr und IEC 60870 bietet nur Kommunikation.

Beim Thema „Kommunikationsstandard“ haben wir mittlerweile mit den vielen neuen Ansätzen bei IEC 61850 eine hinreichende Basis, um die meisten notwendigen Informationsaustauschmechanismen ((Funktions)Modelle, Dienste und Protokolle) implementieren zu können. DER-Modelle (61850-7-420) werden zurzeit beispielsweise am KIT bei der Realisierung mehrerer Forschungsprojekte verwendet ... das sind erfolgsversprechende Ansätze!

Ich würde mich freuen, wenn der Aspekt „überlebensdienlich“ im hier beschriebenen Usecase in Zukunft in einfache technische und sinnvolle Lösungen einen zielführenden Niederschlag finden würde!

Dieser Vorschlag, den ich einigen Experten aus dem VDE-Umfeld vorgestellt habe, hat bereits nach zwei Tagen viele positive Rückmeldungen bewirkt!

Wednesday, July 17, 2019

How to ring the front door bell in case of power outage?

Today I had a phone call with a friend discussing what happens when we suffer a blackout. I was sitting in my home office in the basement when the door bell was ringing. I asked my friend: What would happen, when we would have a power outage here at home?

He sent me a nice picture that I used as an instruction to install a very useful (new) SuperCat bell push at our front door:




If you push the left button ... Auuuuutsch ... we would hear you crying ... haha.

Nice blackout-resisting door bell. I have removed it later ;-)

Thursday, July 11, 2019

Holistic Engineering and IEC Standards


One of the most crucial challenges in Electric Power Systems in the future is the fact that multiple aspects like planning, design, configuration, data acquisition, operation, protection, error detection, maintenance, ... security, ... at several layers (process, asset management, ...) are so co-joined with each other and interdependent.

Is this new? No! Some 400 years (!) ago, Rene Descartes was recommending to apply a holistic approach for all sciences ... he did not know the huge interconnected Power systems in Europe, China, USA, ... here is what he has written [extended by myself]:



I highly recommend to educate young people in a way that they get a holistic understanding of the many aspects of the electric power system ... focusing on one or two aspects may cause at the end of the day many problems. The main aspect still is to understand the physics of such a huge system. Any programmer of software impacting the safety of the power delivery system should be educated in physics and especially electrical systems. So, understanding MMS, IEC 61850 or OPC UA is good - BUT engineers should understand the process (electrical system) they are manipulating with some lines of code. Engineers should also be trained thoroughly in the many aspects.

Unfortunately there is quite often little budget for comprehensive training in several aspects. Ask your management for more training - better:more hands-on training!!

Friday, July 5, 2019

IEC 61850-8-2 Versus IEC 61850-8-1

Many people have complained that IEC 61850 is far too complex ... especially because of the mapping defined in IEC 61850-8-1 as the SCSM (Specific Communication Service Mapping) using ISO 9506 MMS as the carrier to exchange IEC 61850 client/server messages. MMS (Manufacturing Message Specification) offers generic objects (NamedVariables, NamedVariableLists, ...) and services (Read, Write, InformationReport, ...). The application of MMS for IEC 61850 requires to define very tricky mappings ...

Click HERE for downloading the FDIS of ISO 9506-1.
Click HERE for downloading the FDIS of ISO 9506-2.

As the convenor of ISO TC 184/SC WG2 (responsible for MMS for many years) I have supported MMS allover ... and I still do it. It is a solution that works well for years ... especially in the domain of substation automation. Other application domains, e.g., DER devices connected directly to a control center (without the need of horizontal communication with up to hundreds of devices), could make use of a lighter message service and mapping concept. The idea of using webservices was discussed many years ago. The IEC TC 57 set up a team to look into it.

The following document written in 2012 discusses the:

IEC 61850-8-2 Web Services Justification

Excerpt:
"IEC 61850/MMS is an open scalable suite of protocols that can support real-time operation. However, these protocols are not well understood by typical IT professionals that work in these stakeholder environments, even though the rich information models of IEC 61850 meets the semantic needs of the distributed applications. ...
Therefore it makes economic sense to map the rich abstract IEC 61850 information models to the more ubiquitously deployed and understood communication and security profiles.   This requirement can be satisfied by mapping IEC 61850 to web services, which are the most commonly implemented technologies.
IEC 61850/Web Services is not a replacement for MMS used in the substation.  Rather, IEC 61850/Web Services would be targeted to customer environments where information is used to interact with customer-owned equipment, including Distributed Energy Resources (DER) systems and facility energy management systems. In these situations, information flows between utility systems, customer systems, and third party systems, straddling utility and customer ownership, sometimes within a single application deployment.
The stakeholders deploying DER systems understand that IEC 61850 over web services provide least cost protocols to interact with their DER devices because:
Web Services provide greater compatibility with widely deployed IT infrastructures, tools and skills, including cyber security.
..."

Finally the work ended in the following standard:

Communication networks and systems for power utility automation – Part 8-2: Specific communication service mapping (SCSM) – Mapping to Extensible Messaging Presence Protocol (XMPP)

The published document 8-2 uses principles of IEC 61850-8-1 as well as MMS services and protocols! Really? Yes. The main difference regarding message exchange is in the encoding of the MMS messages: 8-1 uses ASN.1 BER and 8-2 uses XML messages (with the structure of MMS services defined as XML Schema). Strange? Yes!

You can find the XML schema for the MMS messages using XML encoding here:

Code component of the IEC 61850-8-2, reflecting the XML namespace described in this document. It includes as well the virtual API with IEC 62351-4.

https://www.iec.ch/public/tc57/IEC_61850-8-2.2018_ed1.0.XSD.2018A1.full.zip

Summary on the protocol issues: IEC 61850-8-2 does NOT provide a direct mapping of IEC 61850-7-2 ACSI models and services to webservices!

I am involved in defining a third mapping (of a subset of services) ... to use JSON schema (and objects) for the models and the messages ... in order to offer really light weight messaging carrying a subset the original semantic of IEC 61850 models!!

We have successfully implemented client and server using http Get and Set services that carry JSON objects representing IEC 61850 Objects.

Example of DataSet and Report (showing the basic idea of mapping to JSON):



The decision to propose the JSON mapping officially to IEC TC 57 is expected later in 2019.

By the way, our granddaughter (20, Student in EE and IT) has implemented this example in Python running on Windows and on two Raspberry Pi3 (one playing the role of server and the other one as client).

We expect that this mapping will push the application of IEC 61850 models and services in domains that need simple solutions that can be programmed by many engineers and programmers.

The JSON mapping could easily be used as an interface from an original IEC 61850 Server (e.g., a bay controller or protection device) to underlying systems:



Sample JSON response from our Fronius PV Inverter with some values:

Request:
http://192..../solar_api/v1/GetInverterRealtimeData.cgi?Scope=Device&DeviceId=1&DataCollection=CommonInverterData

Response (JavaScript):



Stay tuned to learn more ...

Tuesday, July 2, 2019

1 MWh Electric Energy May Cost 37.856 Euro - You Don't believe it?

Belief me, this is true: You could have sold 1 MWh electric power to the German Grid for 37.856 Euro the other day (used for primary frequency control) - if you would have had the opportunity to sell it on the spot market ...

We have our roof PV system some 10 kWp since Sept 2016. The energy produced since then is 25 MWh ... this would sum up to 25 x 37.856 Euro = 946.400 Euro !! WOW !! Unfortunately I did not have the opportunity to influence the German electricity market and to make such a sale ...

See some news in German regarding the situation.

Something went wrong on the 6., 12. and 25. June 2019.

The belief in the Market to fix everything ... may end up in a big blackout.

Add-On (2019-07-03):

Today I found more details on the reasons why we were so close to big trouble:

"Due to a faulty data package, the European electricity
exchange EPEX in Paris decoupled the European
electricity market on June 7, 2019. This caused a great
deal of excitement on the markets. Johannes Päffgen,
Head of Energy Trading at Next Kraftwerke, explains the
causes and consequences in an interview.
Christian Sperling: Johannes - What happened? Why
was there so much trouble at EPEX on the Friday before
the Whitsun holidays?
Johannes Päffgen: Well - in the end it's a computer error... but we should go into that later. At about 11:40 this Friday we noticed that something was wrong at EPEX. We couldn't place any more bids for the day-ahead electricity auction on Saturday. ..."

Clicke HERE for the full report.

I guess it was a human error ... somebody didn't take into account that corrupted data packages will be sent and received ... how could a faulty package have such a dangerous result?!?!

Unbelievable.

Stay tuned for more information once available.

Monday, July 1, 2019

IEC TC 57 Just Published Amendment 1 of FDIS of IEC 61850-9-2

The following FDIS has been published last week:
57/2112/FDIS

Amendment 1 – Communication networks and systems for power utility automation – Part 9-2: Specific communication service mapping (SCSM) – Sampled values over ISO/IEC 8802-3

The ballot closes: 2019-08-09

Compared to the second edition, this first revision of the second edition:

a) updates the normative references
b) adds a synchronization clause (Clause 9); adds references to IEC 61588:2009 and
IEC/IEEE 61850-9-3 for SV synchronization;
c) modifies physical layer specification in T-Profile;
d) modifies MSVCB components (Table 9 and Table 10);
e) deprecates usage of USVCB;
f) modifies encoding for the transmission of the sampled value buffer (Table 14);
g) adds Table 20;
h) adds Table 21;
i) adds Annex C related to possible backward compatibility issues between revisions of this
standard;
j) provides clarifications and corrections to the second edition of IEC 61850-9-2, based on the
tissues = { 1349, 1272, 1055, 944, 863 }.

Saturday, June 22, 2019

Dangerous Situation in the European Electric Power System Caused by "frozen" Measurements

Measurements of power flow (Watts in export or import) are very crucial for Load Frequency Controller … wrong (i.e., “frozen”!) measurements have caused almost a big blackout in Europe in January 2019.
What happened: the measurement of power of the lines between two transmission systems (Germany – Austria) were frozen when the export value of 723 MW from Germany to Austria was measured (which was a result of 34 GW wind power generation in Germany). Later the wind power generation decreased to 4 GW … and the measurement (as input to the controller) many hours later still used the input value of 723 MW !!! In such a meshed power network it is unlikely that such a value is constant …

Oops … something went absolutely wrong!

Report by exception (on a value change as used for the above measurement) is great … as long as there are changes figured out and reported. A frozen value does not cause a change and thus no new value will be reported … No receiver should expect that the export power is constant (723 MW) for days!! The sensors may have worked fine … but the software and communication failed … on both sides (sender and receiver). A receiver should not trust that the software and communication is working fine all time.
Here are some measures to monitor the communication (by the receiver) to figure out if the communication is OK:
  1. Ping (in case of TCP/IP) (if no response after some time: raise flag)
  2. TCP Keep-alive (if no keep-alive message in t bigger keep-alive: raise flag)
  3. Polling by receiver (if no response after some time: raise flag)
  4. Periodic reporting (if no report in t greater period: raise flag)
  5. In case of no message received in a configured time period (in case of using IEC 61850 Reporting) the receiver should check if the report control block is enabled and is using the correct configuration values like trigger option, …
  6. Check if the sequence of received values are plausible
  7. Use redundant systems (comm, …)
Check out the official Entso-E report (with links to more details):

https://www.entsoe.eu/news/2019/05/28/entso-e-technical-report-on-the-january-2019-significant-frequency-deviations-in-continental-europe/

This reminds me on the Boeing 737 MAX disaster … maybe a programmer left the vendor of the load frequency controller and hired with Boeing … I am kidding.

How many programmer or people that configure power control systems and communication systems that lack experience with complex systems like a plane or a power system. Where are the “grey-hair” experts that would tell you in minutes how to … ? They may enjoy the beach with warm water and sun shine – relax and spend the pension for ...

It is not sufficient to have no ideas – one should also be unable to implement them.

I expect that more of these problems will hit the street once we have far more control, monitoring and communication in the smart(er) grids of medium and low voltage. Note that the problem in January 2019 occurred at transmission level!! … where more resources (higher budgets) are available (in the past).

Have a great weekend – with power.

Wednesday, June 12, 2019

The IEC 61850 Tissue Database is a Great Resource of Hints and Background Information

The IEC 61850 tissue database is a comprehensive resource of hints and background information that can help you to understand why a particular change or correction has been implemented:
https://iec61850.tissue-db.com

Many tissues are posted that end up in the category "blue" (This is a question only). The discussion of the experts is often very helpful ... here you find answers that you may not get from the original published documents.
Example of discussion:
https://iec61850.tissue-db.com/tissue/1649



Enjoy the tissue database. As a registered user you can post tissues and see more details.