7/27/2019 04840228

1/5

Testing IEC 61850 BasedMulti-vendor Substation Automation Systems for

Interoperability

Jian-Cheng (J.C.) Tan,Member IEEE, Vince Green,Member IEEEand John Ciufo, Hydro One Networks Inc.

Abstract--Verifying interoperability is part of the sitecommissioning test to ensure an IEC 61850 based substation

automation system will function as it should. It is vitally importantto check all virtual point-to-point logical connections associated

with a distributed function, especially if GOOSE tripping over theLAN is part of the scheme. This paper discusses the types ofinteroperability testing in-house and on-site, and the issues that

make it necessary. The paper also presents the interoperability

testing initiative sponsored by Hydro One conducted at theKinectrics Interoperability Testing Lab, where IEDs and systems

from seven major manufacturers are connected to the Testing LANand exchanging information via the global standard IEC 61850.

An interoperability testing case is given in the paper to demonstratethe interoperability between IEDs and systems from ABB, AREVA,

GE, SEL, and Siemens, which are connected to a Test LANconsisting of a couple of RuggedCOM switches.

I. INTRODUCTION

The new global communications standard IEC 61850 ison its way to broad-scale deployment, with hundreds ofsubstations already implemented and in operation with many

more planned. It is evident that, in the near future, every utilityin the electrical power industry will have to deal with IEC61850 to reap the full benefits of integrated protection,control, and monitoring systems. An IEC 61850-basedapproach offers many benefits, including the following:

Effortless integration with all third-party IEDs. Thisprovision assumes that market-available IEDs, systems, andtools are mature, and that engineers are already trained andhave mastered the technologies.

Seamless communication with EMS/DMS/SCADA systemeliminating box-in-the-middle devices such as RTUs andGateways. This provision assumes utility-wide deployment

and harmonization between IEC-61850/IEC-61970/IEC-61968 has been achieved. Direct access to all control points in the substation locally

and remotely. The distributed solution that replaces thecentralized RTU solutions eliminates the bottleneck andprovides increased system reliability.

Free allocation of functions into IEDs, offering unparalleledflexibility

Plug and play design provides unmatched scalability andexpandability

Significant cost reduction in design, integration,engineering, commissioning, operation & maintenance

Total elimination of electromagnetic interference on thesubstation control room if merging unit or optical transducertechnologies are employed. This provision assumes themerging units are located in the switchyard with only fiberoptic cables to the control room.

Improved CT/PT availability with process bus applications.

Conformance testing can reduce a number of costlyissues and problems during integration, site commissioning,and operation. However, devices that have passedconformance testing may still be subject to issues duringintegration, commissioning, and operation. Therefore,interoperability testing is necessary before in-houseintegration and to gain confidence before field deployment.Conformance testing cannot replace interoperability testing.

II. THE NEED FOR INTEROPERABILITY TESTING

IEC 61850 is a global standard that facilitates the

interoperability between all third-party IEDs in substations.Interoperability is the capability of two or more intelligentelectronic devices (IEDs) from one or several vendors toexchange information and to use it in the performance of theirfunctions for correct co-operation [1]. More precisely, it is afunction performed by several devices from the same ordifferent vendorsthe distributed function. Theaccomplishment of a distributed function relies upon theinformation exchange mechanisms, the modeling methods asdefined in IEC 61850 and implemented in all devices, and thenetwork where these IEDs are connected.Only conformance testing is defined in the IEC 61850standard. Interoperability testing is not in the scope of IEC

61850. IEC 61850-10 conformance testing provides aguideline on what to test. UCA International Users Group(UCAIug) defines how to test. It should noted that mainly thecommunications interfaces are tested using the conformancetesting suite. Connections between the relay application andthe communications interfaces are too complex to be tested[3]. This may not necessarily be true. It is evident thatinteroperability testing involves the network connections andassociated functions, which is indeed much more complicatedthan a single device to be tested in an established testingenvironment.

978-1-4244-3811-2/09/$25.00 2009 IEEE

7/27/2019 04840228

2/5

Interoperability testing is always associated with the specificdevices and systems under testing, the network connectingthese devices and systems, and the application functions thatare associated with information exchange. Given the vastnumber of IEDs commercially available on the market that arecompliant with the IEC 61850 standard, the variation innetwork architectures, the free allocation of functions in IEDsin IEC 61850 based substations, and the many functions thathave been defined and modeled, comprehensiveinteroperability testing of all possible products over all typesof network architecture is not feasible.

While conformance tests help vendors discover childhooddiseases of the product during development phases,interoperability testing provides the end-user the desiredconfidence that the system will interoperate as it should.Interoperability testing can be either a proof-of-concept test inthe lab or can be conducted as part of a site acceptance test.The former usually is conducted by the substation designengineers or system integrators to gain assurance before in-house integration and field deployment of the project. Thelatter is part of the site commissioning test to ensure data will

flow on an optical fiber LAN as it is designed. Point-to-pointchecking of all virtual connections over the substation LAN isvital to the correct operation of the substation automationsystem and the reliability of the entire power system.Interoperability tests based upon the purpose of testing can becategorized as follows:

Proof-of-concept interoperability testProof-of-concept interoperability testing verifies thecommunication interfaces associated with the IEDs undertest. The test usually is conducted in-house to verify if thespecific IEDs are able to communicate with each other.The connections between the IEDs are usually simplified

for best effort testing, and the functions associated withthe interoperability are generally not tested.

Site acceptance interoperability testSite acceptance interoperability testing verifies the point-to-point communications over the substation Ethernet LAN. It isvitally important to check all virtual point-to-point logicalconnections associated with a distributed function as designed.A test set is required to simulate the substation secondaryconditions either by generating the desired analog or digitalcurrent and voltage signals to initiate the test.Conformance testing cannot replace interoperability testing. Itshould noted that manufacturers usually conduct interoperability

testing within their own product lines; co-ordination and dataprivacy are usually not an issue within the same manufacturer.However, interoperability between multiple devices and systemsfrom multiple vendors are usually not fully tested. Two devicesthat have passed conformance testing may not be 100%interoperable with each other because they have differentcommunication profiles. Interoperability testing between multi-vendor devices and systems is highly recommended to gainconfidence before in-house integration and field deployment.

Interoperability tests based on vendors, therefore, can beclassified as one of two types:

Single-vendor multi-device interoperability testsAll devices and systems under test are from the same vendorwithin the same platform where all IEDs and systemsshould conform to the standard and pass the conformanceand factory acceptance tests. Usually only the vendor-basedproprietary IED configuration tool is required forconfiguration.

Multi- vendor multi-device interoperability testsDevices and systems under tests are manufactured bydifferent vendors across different platforms. These IEDsand systems under testing should have passed theconformance testing and would need the proprietary IEDconfiguration tool as well as a system-level configurationtool for data flow engineering.

A peer-to-peer communication profile is a unique feature of anIEC 61850 based substation automation system. Peer-to-peercommunication enables interoperability between deviceslocated at the bays as well between station-level devices andsystems. Client server profiles, meanwhile, are usuallybetween bays and station levels. Interoperability tests based

upon the communication profiles can be categorized as:

Peer-to-peer profile-based interoperability testThe test verifies the point-to-point virtual logicalconnections between two or multiple devices over theSubstation Ethernet LAN. Any one of the devices caninitiate the test via multicasting a datagram onto the LAN.The other parties involved then listen and capture it if it isdesigned for them.

Client-server profile-based interoperability testThis is a connection-oriented profile; the connection mustbe established before the testing. The server is always the

initiator. When an event occurs, the server pushes themessage /datagram up to the client. The servers areusually located at the bay level while the client is usuallysitting at the station level.

In a substation environment, devices located at the bay levelmay interoperate with each other. These devices may alsointeroperate with devices and systems such as HMI and Datawarehouse etc. at the station level. Interoperability tests basedupon the substation hierarchy can be classified as:

Horizontal interoperability testHorizontal interoperability testing involves the devices

located at the bay levels communicating via a peer-to-peerprofile over the Ethernet LAN. The devices interoperateover a connectionless-oriented Ethernet; therefore it isvital to check all virtual point-to-point links and to verifyif the distributed function is indeed interacting as it shouldduring the commissioning test. It may require secondaryinjection to cause the IED to generate the initial signal, ifconventional instrument transformers are applied.

Vertical interoperability testAs the name indicates, vertical interoperability testinginvolves devices at the bay level as well station level

7/27/2019 04840228

3/5

The Integration Procedures

1. Generate ICD or CID filesEach IED produces a self-description IED Capability Description ( ICD or CID ) file with theinformation required for exchange already configured for GSSE/GOOSE publication.The file extension, which can be CID or ICD, must contain the following specific IED configurations:

IED Name

IP address Multicast MAC VLAN ID Etype AppID Publishing GOOSE dataset information

This part remains as proprietary, must be preformed by the vendor-specific IED configurator tool.

2. Configuring the data flow between IEDsImport ICD/CID files generated from (1) into a System Configurator such as Digsi 4.8. Theinformation published from each IED will be auto-displayed in the source window ready to beconfigured.

Configure the data flow between IEDs by subscribing the published GSSE/GOOSE messages. Onceall configuration is done, export the project configuration to create the Substation ConfigurationDescription ( SCD ) file.

3. Send back the CID filesFeed back the SCD file to the IED configurator, where the specific CID file will be extracted anddownloaded into the IED. The data flow information should not be changed by the IED Configurator.

Figure 1 The Integration Process

communicating via either peer-to-peer profile or client-serverprofile. Functions such as controlling a breaker from the HMIusually via the client-server communication, or peer-to-peerwhere fast interlock is necessary, require verticalinteroperability testing.

III. INTEGRATION

A departure from the traditional approach is the simplifiedcabling and in-house integration in IEC 61850 basedsubstation automation systems. Much of the detailed DCschematics related design is now replacedby a simple GOOSE table. This elimina tes the labor-intensive cabling engineering and replaces it with aplug-and-play solution consisting of in-house integration. It isvitally important that interoperability testing on point-to-pointvirtual logic connections should be conducted to ensurecorrect operation of the substation automation system.

Many phases are involved in the integration of IEC 61850based substations. Horizontal integration involves IEDspublishing and subscribing to GOOSE messages at the baylevel. Across the bays to the station level, for example, a DataManager or Data Concentrator collects data from all

substation IEDs. This is a typical application that needsvertical integration. A system integrator collects the IEDCapability Description (ICD) files usually containing theGOOSE publications from all IEDs in the substation. Theseconfiguration files must be created by the vendor-basedproprietary configuration tools, either in a template ICD form,or a specific ICD file that must contain the published GOOSEmessages if dynamic dataset is supported. For this reason (theconfigured GOOSE publication), some manufacturers believefiles to be imported should be CID files instead of ICD files.

IED configuration tools remain proprietary. The functions of

an IED configuration tool include: Create an ICD file from template Export ICD files with pre-configured GOOSE

publication Import SCD files from System Configuration tool Download CID file into the IED.

It should noted that a SCD file may contain many CID files.These files may overload the IED configuration tool withunnecessary third-party CID files, which the IEDconfiguration tool may incapable of accommodating at all. It

7/27/2019 04840228

4/5

7/27/2019 04840228

5/5

Figure 3 Transfer Trip Scheme

VI. REFERENCES

1. Communication networks and systems in substations.Part 10: conformance testing.

2. Communication networks and systems in substations.Part 6: Configuration description language forcommunication in electrical substations related to IEDs.

3. Hachidai Ito, Kenichiro Ohashi, and Shigeki Katayama:Implementation of High Performance IEC 61850GOOSE and Protection Relay Testing, GRIDTECH2007, International Exhibition and Conference, 5th & 6 thFebruary, 2007, Pragati Maidan, New Delhi, India.

4. Eric A. Udren and Dave Dolezilek: IEC 61850: Role ofConformance Testing in Successful Integration.www.selinc.com/techpprs/6242_61850Role_DD-EU_20060519.pdf.

5. Bruce Muschlitz: IEC 61850 Conformance Testing:Goals, Issues and Status, DistribuTECH 2006,http://www.enernex.com/staff/docs/Muschlitz61850conftest.pdf

6. Ivan De Mesmaeker1, Peter Rietmann, Klaus-PeterBrand, and Petra Reinhardt: Substation Automationbased on IEC 61850, Cigr SC B5 6th Regional CIGRconference in Cairo, November 21 23, 2005.

7. Maciei Goraj and Juergen Herrmann: Experience in IEC-61850 and Possible Improvements of SCL Languages,PRAXIS PROFILINE IEC 61850 April 2007.

8. Brian Smith and Darren Highfill: TVA Investigates End-to-End Integration, T&D World, July 2007.

9. Victor Manuel Flores, Daniel Espinosa, Julian Alzate, andDave Dolezilek: Case Study: Design and Implementationof IEC 61850 from Multiple Vendors at CFE La VentaII.http://www.selinc.com/techpprs/6271_CS_DesignImplement61850_JA&DD_20070406.pdf.

10. Craig Wester, G. E. Multilin, and Dr. Juergen Holbach,Siemens Power T&D: Status of the First IEC 61850Based Protection & Control Multi-Vendor Project in theUS. The 60th Annual Conference for Protective RelayEngineers, Texas A&M University, March 2007.

11. Tim Tibbals: Case Study: Design and Implementation ofIEC 61850 from Multiple Vendors at CFE La Venta II.The 60th Annual Conference for Protective RelayEngineers, Texas A&M University, March 2007.

12. Chris Ruckman and Rich Mahaley, Burns & McDonnell:Application of IEC 61850 for Power Plant Relaying.The 60th Annual Conference for Protective RelayEngineers, Texas A&M University, March 2007.

13. Benton Vandiver: Functional Testing of IEC 61850Based Protection Relays. The 60th Annual Conferencefor Protective Relay Engineers, Texas A&M University,

March 2007.

t/s0.005 0.010 0.015 0.020 0.025 0.030 0.035 0.040 0.045

Hard wired Trip 1Transfer Trip 2GOOSE Trip 1