Investigating Interoperability for IEC 61850 Technology

Authors: H. Krings, P. Wittlinger, A. Schröder, FGH e.V., J. Kurrat, ABB AG, G. Druml, A. Eberle GmbH & Co. KG,M. Häcker, Schneider Electric, Germany, S. Thompson, Alstom, UK, M. Mainka, Maschinenfabrik Reinhausen GmbH, H. Englert, Siemens AG, Germany

InterOP-a research project

InterOP Project Scope: The aim of the research project was to investigate how the present standard supports the implementation and setup of interoperable system environments. The scope of the project is limited to IEC 61850 Edition 1 devices and applications. Usage of compliant devices is necessary but not sufficient to achieve interoperable systems. Additionally there is a need for defining system-wide aspects concerning communication and engineering. The result of the project is a set of recommendations to be taken into account for achieving system-wide interoperability.

In a first step, a Functional Specification [INTEROP_FS] giving an abstract description of the test case functionalities was set up. It is based on typical applications and examples used in substations of large electric grids taking into account parts of the DKE IEC 61850 substation model. The following test cases were defined:

  • Control blocking
  • MMS file transfer
  • Switching by Select Before Operate with interlocking
  • Reverse blocking
  • Autoreclosure coordination
  • Busbar voltage replica
  • Switching with synchrocheck function
  • Substation supervision
  • Earthfault detection
  • Frequency relay function
  • Automatic neutral current regulator (Petersen coil regulator)
  • Automatic OLTC controller
  • OLTC Monitoring

Based on the Functional Specification giving an abstract description of the test case functionality the Test Specification [INTEROP_TS] has been derived describing the test case setup for all IEDs and their interaction with further equipment and explicitly describes the information flow between devices.

Following the specification stages an engineering stage has been performed to set up the comprehensive substation configuration description for describing the functionality and communication of the test system. Tools from different vendors involved in the project were used to perform the engineering which involved an exchange of ICD/CID files between tools and vendors. System engineering was executed by three independent system configurators. For setting up the system-wide communication configuration of reporting and data flow was defined before starting SCL engineering.

Finally, the testing phase was carried out based on the test scenarios defined. The tests were executed at FGH e.V. [FGH] facility in Mannheim, Germany, where a mobile test system (see Figure 2) was built up and where all tests were executed and evaluated. During these tests the observed issues have been verified and subsequently been analysed. The test results are outlined in the InterOP Test Report [INTEROP_TR] that is available for download at the FGH homepage.

System Description: InterOP research activities are based on tests running on a real physical system environment as shown in Figure 3. For setting up and executing tests on practical and common applications the project partners agreed on using a topology based on the resulting substation model of DKE AK 952.0.15 “GAK 15” (Release Feb. 2006) [DKE_MODEL]. In order to provide the necessary substation-structure for carrying out all scheduled tests of the Test Specification, the “GAK 15” substation model was modified. It is not designed for representing a complete substation but for representing typical functionalities used in substation operation. All IEDs, involved in the tests, are shown in the figure and have an unambiguous naming according to the bay. E.g. an IED named “IED 1.1” which provides both protection and control functionality as identified by its unambiguous ID “E1Q1FP1”. Intentionally each test involved a specific constellation of IEDs from different vendors which are referenced in the basic test descriptions of the Test Specification.

Figure 1 shows the principal test communication system. The network consists of three switches. Switch 1 and switch 2 directly connect all server devices and switch 1 provides a mirror port which represents all traffic on all ports, the communication between all servers as well as to and from all clients via an uplink connection to switch 3.

A single analysing PC was connected to the mirror port in order to capture the entire traffic of the system for post analyses, taking into account not only the traffic between the servers but also between servers and clients. Switching devices, analogue and digital signalling were simulated by external equipment. Via switch 3 HMIs and equipment like an SNTP server were connected. A VPN remote access provided general accessibility for engineering purposes, exchanging configurations, setup and log files.

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