cim-iec 61850 interactions during run...

13 June 2013

CIM-IEC 61850 Interactions During Run Time

R. Santodomingo, S.Rohjans, M. Uslar (OFFIS) J.A. Rodríguez-Mondéjar, M.A. Sanz-Bobi (COMILLAS)

Presenter

Presentation Notes

I’m going to present some results from our research about how to facilitate the run time interaction between IEC 61850 based systems and CIM based systems.

2 Instituto de Investigación Tecnológica Escuela Técnica Superior de Ingeniería ICAI

CIM-IEC 61850 Interactions During Run Time – J.A. Rodríguez-Mondéjar 13 June 2013

• Introduction • Objectives and Scope • Fundamentals • Proposed Methodology • Case Studies • Experimental Results • Conclusion and Future Work

Contents

Presenter

Presentation Notes

Well, this is the index of my presentation.



Introduction

Proxy

IED IED

Network Operation Repository

SCADA

Network Operation Simulation

CIM-based Management System

IEC 61850-based Automation System

Configuration: SCL

Run Time: LN

Two Data Models

Presenter

Presentation Notes

The automatic translation of data from 61850 based systems and CIM based systems is not a trivial question. Please, If you don’t believe me please ask to Terry Saxton. Why is not a trivial question? In one hand, the 61850 defines two models: the SCL model oriented to configure the communications and the logic of devices which control the substation; and the LN model who defines the core of the messages that exchange the 61850 devices. In the other hand, in the interaction between CIM and 61850 we must consider two time frames: configuration time and run time.



Introduction • In Configuration Time (I)

CIM-SCL Harmonization - IEC TC 57 WG 19 - ABB (T. Kostic, O. Preiss) - EPRI (T. Saxton, H. Falk)

Proxy

IED IED


SCADA




SCL-

CIM

Presenter

Presentation Notes

If we put the focus in configuration time, the efforts on the harmonization between the CIM and the SCL model based on the EPRI works commanded by Saxton and Falk will enable the bi-directional flow of CIM and SCL configuration files without any information loss. But, with the actual models the direct translation is not possible. For example, the SCL models all type of disconnector using only one class and CIM uses a class per type of disconnector.



Introduction • In Configuration Time (II)

Proxy

IED IED


SCADA




ESODAT

SCL

CIM

R. Santodomingo, J.A. Rodríguez-Mondéjar, and M.A. Sanz-Bobi, “Using Semantic Web Resources to Translate Existing Files Between CIM and IEC 61850,” IEEE Trans. Power Syst., vol. 27, no. 4, pp. 2047-2054, Nov. 2012.

Presenter

Presentation Notes

At this point, we have developed a generic data translator, called ESODAT, to cover the transition period until the utilities only use harmonized CIM and SCL models. More details about how ESODAT works are available in the article “Using Semantic Web Resources to Translate Existing Files Between CIM and IEC 61850”.



Introduction • In Run Time

Proxy

IED IED


SCADA




Gateway

CIM-LN Signal Mapping • Manual Process • Human Errors • Time Consuming

Presenter

Presentation Notes

The problem of interaction between CIM and LN signals is worst than configuration file interoperability. From ours acknowledge, there are not solution in the literature aimed at automating the mapping of 61850 signals and CIM measurements. At present, the mappings that the gateway uses must be carried out manually. It’s a time consuming process and many human errors may occur.



Objectives and Scope

• Helping to automate the CIM-LN signal mapping

• The specific technology used in the gateway is not within the scope of this work

Presenter

Presentation Notes

That’s why in this work we proposed a methodology that helps to automate the signal mapping between CIM and 61850 systems. However, the specific technology used in the gateway that will use these mappings is not within the scope of this work



Fundamentals • IEC 61850 (I)

– Logical Node Model (LN) • IEC 61850-7

– Text Tables

Server

Logical Device (LD)

Logical Node (LN)

Data Object (DO)

Data Attribute (DA)

ServerLD/LN.DO.DA

IED1

C1

QA1CSWI1

Pos

stVal

IED1C1/QA1CSWI1.Pos.stVal

IED1

QA1

QA1CSWI1

Prefix: Cond. Equipment (QA1) LNClass: IEC 61850-7-4 (CSWI)

Sufix: LN instance (1)

C1 QA1CSWI1 - Pos - stVal

Presenter

Presentation Notes

First, some fundamentals for a better understanding of our methodology. As I said before, the 61850 defines two models: The Logical Node model for run time. And the SCL model for configuration file or configuration time. The Logical node model is defined in IEC 61850-7 using actually text tables. The logical node model represents the run time information using a hierarchical approximation: Every value or data attribute is inside a data object. The data object is inside of a logical node who represents a functionality. The logic node is inside of a logical device that represents devices that perform supervision, protection or control functions. The logic device is inside of a server that represents physical intelligent electronic devices (IED). For example: The IED1 has a logical device named C1. C1 has logical node QA1CSWI1 that has an attribute Pos for representing the position of a switch. And stval is the actual position of the switch. The name of the logical node is expressed as the concatenation of the type of logical device (switch controller), a prefix with something related with the real name of the switch, and the suffix that is the number of the logic node instance.



Fundamentals • IEC 61850 (II)

– Substation Configuration Language (SCL) • IEC 61850-6 • XSD

tLNodeContainer

tConductingEquipment

tLNode

tDO

tDA

Presenter

Presentation Notes

The substation configuration language (SCL) uses a similar approach using the schema definition (XSD). It uses classes as tDA, tDO, tLNode and tLNodeContainer for representing the LN signals allocated in a device. A specific configuration file represents what we are using from the capacities of one IED.



Fundamentals • CIM

• IEC 61970/61968/62325 • UML

Discrete

Measurement

Analog

MeasurementValue

AnalogtValue

DiscreteValue

Discrete measurementType = “SwitchPosition”

DiscreteValue value

Presenter

Presentation Notes

In the other part, CIM uses the Discrete and the Analog classes to represent discrete and analog measurements or signals. The associated values is represented with instances of DiscreteValue or AnalogValue classes. For example, the position of a breaker is represented in CIM with a DiscreteValue instance associated to a Discrete signal or measurement with type = “SwitchPosition”



Fundamentals • CIM-LN Signal Mapping

tDA name= stVal

SCL file CIM file

tLNode lnClass = CSWI

Discrete

DiscreteValue value

Discrete

DiscreteValue value

Discrete

DiscreteValue value

Discrete

DiscreteValue value

CSWI.Pos.stVal = cim:DiscreteValue.value

QA1

tDO name= Pos

Brkr1

IEC TC 57 Reference Architecture - Generic CIM-LN mappings

Presenter

Presentation Notes

Regarding the CIM-LN signal mappings, the IEC proposes generic mappings, that are useful but not sufficient. For example, they propose this mapping: But with this mapping we can not know that the signal position of QA1 in the SCL file corresponds with the signal position of BRQ1 in the CIM file. Why, because typically names that CIM uses don’t match with names used in SCL.



Fundamentals • Ontology Matching

– Ontology • Describe domain knowledge in a machine-processable way

– Language: owl (xml, xsd, rdf, owl,…) • Powerful reasoning services associated

– Ontology Matching • Methods to automatically find semantic correspondences

(alignments) between different ontologies

Presenter

Presentation Notes

How to solve the problem? Our proposal is using ontology matching techniques. An Ontology is a technique that describe domain knowledge in a machine-processable way. If we have data and his relations in a machine tractable language we can use powerful reasoning services. One of this service is ontology matching that automatically find semantic correspondences between differente ontologies.



Proposed Methodology • 3 Steps

Presenter

Presentation Notes

We proposed this methodology that comprises three steps: In the first step the OWL ontologies are created (..OWL lenguaje estándar de facto para representar ontologías) Then, an ontology matching system developed in this work helps to find the alignments between the ontologies From the alignments the signal mappings are obtained



Proposed Methodology • Gateway

Presenter

Presentation Notes

It’s important to point out that, once the signal mappings are obtained, engineers must revise them carefully before programming the gateway. The methodology expresses the signal mappings in an Excel table (which can be easily interpreted by engineers) Additional, it expresses the mappings in Jena Rule Language (well-known language for representing transformation rules). This enables that a gateway based on the open-source Jena Reasoner could carry out bi-directional translations between LN signals and CIM measurements.



Proposed Methodology • First Step: Generating the Ontologies

Enterprise Architect

TC 57 WG 13 & WG 14

Uml2Owl

ESODAT

LN OWL

TC 57 WG 10

SCL OWL CIM OWL

IEC 61850-6 (SCL Schema)

IEC 61850-7 (LN text tables)

Xsd2Owl

Presenter

Presentation Notes

In the first step -> Generating the Ontologies The CIM ontology automatically obtained with the Uml2Owl conversion in CIMTool The SCL ontology automatically obtained with the Xsd2Owl conversion implemented in ESODAT The LN ontology -> for this work a simplified ontology (only two classes) was developed with Protégé ontology editor. This ontology enables the representation of LN signals



Proposed Methodology • Second step: Ontology Matching System

SCL OWL CIM OWL

ESODAT Ontology Matching System

cim:Breaker(?x) -> scl:tConductingEquipment(?x) & scl:type(?x, “CBR”)

tConductingEquipment type = “CBR” Breaker

Key: different names but they represent similar data

Presenter

Presentation Notes

In the second step of the methodology the alignments between the ontologies are found We have developed a powerful tool called ESODAT that builds the alignments between the CIM ontology and the SCL ontology. In the test that we have made, out tool outperforms the best ontology matchers available as the AgreementMaker from the University of Illinois at Chicago. Our average success ratio is 64%. The average ratio of AgreementMaker is only 24%. Here, you have an example of alignment between switch in the CIM model and in the SCL model. I must to remark that we have found these correspondences automatically without modifying the original models.



Proposed Methodology • Third Step: Signal Mappings

Presenter

Presentation Notes

From the original SCL file our tool builds a CIM file Also, our tool builds the measurements CIM file, Then, it compares the built CIM, the original CIM file and the built measurement file with the signal matcher to build the signal mapping. Finally, the signal mapping extractor builds the signal mapping tables and the signal mapping expressed in the Jena rule language.



Case Studies

CIM-IEC 61850 signal mappings for: - State and Control of the Switches - State and Control of the Tap Changers - Analog values of Current and Voltage - Settings of the Synchrocheck Relay

IEC 61850-6

Defined by Spanish electricity

companies

Presenter

Presentation Notes

To proof that our tool works, we have tested with 4 cases. The radial case corresponds to the example that appears in the 61850-6. Type_1, Type_2 and Type_3 corresponds to three typical cases defined by the Spanish electricity companies. In this case the tool calculates the signal mappings for …



Experimental Results • Evaluation Measurements

• Recall: Ratio of correct mappings (true positives) to the total number of reference mappings

• Precision: Ratio of true positives to the total number of returned mappings

• Accuracy: Recall * (2 – 1/Precision) • If Accuracy > 0, the automatic mapping is useful

Presenter

Presentation Notes

We use the parameters recall, precision and accuracy widely used in ontology matching to determine the usefulness of our solution. From ontology point of view our solution is very useful.



Experimental Results

Presenter

Presentation Notes

This is an example of the mappings obtained by the implementation First, the Topology matcher matches breakers in SCL and CIM files Then, the Signal Matcher compares the associated measurements, and finds the signal mappings




Presenter

Presentation Notes

- The extract from the Excel Table created by the implementation including the mappings of the example is shown in this slide…




Presenter

Presentation Notes

- Additional tests were carried out with the aim of determining whether Jena Reasoner performs valid transformations from the signal mappings created by the proposed implementation…



Conclusion and Future Work • Methodology for automatically finding signal mappings

between CIM-based and IEC 61850-based systems

• Although the signal mappings is not completely automated: – SCL and CIM ontologies created automatically – 64.06% of SCL-CIM alignments found by proposed ontology

matching system (best contribution before 24%) – 73.1% of the signal mappings found by the implementation

developed in this work (first contribution in the literature)

• The methodology reduces both the integration effort and human errors compared to manual mapping

– It can work in parallel with manual mapping or semiautomatic techniques based on manual mapping for detecting errors.

• In future work, new ontology matching techniques will be studied to improve the success ratio.



More details • paper "Facilitating the Automatic Mapping of IEC 61850

Signals and CIM Measurements“ will appear on IEEE Transactions on Power Systems (September or October)

• Phd Tesis: “USING SEMANTIC WEB RESOURCES TO ACHIEVE METADATA INTEROPERABILITY IN THE SCOPE OF FUTURE SMART GRIDS”

– Author: Rafael Santodomingo Berry • Dissertation defense : June 24th

Instituto de Investigación Tecnológica Santa Cruz de Marcenado, 26 28015 Madrid Tel +34 91 542 28 00 Fax + 34 91 542 31 76 [email protected]

www.upcomillas.es

THANKS

Rafael Santodomingo Berry [email protected] J.A. Rodríguez-Mondéjar [email protected]

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