Protection History

Authors: Walter Schossig, Germany, and Thomas Schossig, OMICRON electronics GmbH, Austria

IEC 61850 - The Implementations

In the last issues the way to IEC 61850 was described. We explained the activities of UCA and EPRI, covered MMS. Ethernet entered the substation and first interoperability events took place. Later the history of GOOSE was covered. Now we are going to describe implementations in Intelligent Electronical Devices (IEDs) delivered as standard equipment for substations.
Later we will talk about experiences in multivendor projects showing the interoperability capabilities of the standard and describe selected technical solutions. The information is based on selected material and statements delivered by the different vendors or is taken from the Internet. Naturally this article makes no claim to completeness. Vendor’s information are randomized, neither considering chronological order nor rating them. Any comments and further inputs are most welcome.

As an example for GOOSE implementations GE was already mentioned in the last issue. For GE it was obvious that we move into the digital age. Thousands of analog and digital data points are available in a single Intelligent Electronic Device (IED) and communication bandwidth was no longer a limiting factor. Substation to master communication data paths operating at 64,000 bits per second have been becoming common-place with an obvious migration path to much high rates.
With this migration in technology, the “cost” component of a data acquisition system has now become the configuration and documentation component. So an architecture has been proposed which is common until now (Figure 3).
The only change since that are really the communication bandwidths. An early setup utilizing several devices can be seen in Figure 1. Papers by Dave McGinn, Paul Myrda and Bogdan Kasztenny proposed the application for lockout operation and demanded high performance GOOSE. So it extended station bus applications by process bus.

The protection and control system presented in 2008 is based on an architecture that incorporates application-driven requirements for performance, maintainability, expandability and reliability through the use of remote I/O devices to collect CT/VT signals and process control and status signals. In the presented system, these remote I/O devices (Bricks, Figure 2 and Figure 7), fulfill the role of IEC 61850 merging units.
The IEC 61850-9-2 sampled value output of each Brick is connected via pre-terminated fiber cable to a cross connect panel that directs the appropriate signals to each relay.
The system includes Bricks mounted at the primary apparatus, relays, pre-terminated cables, and fiber cross connect panels for patching from Bricks to relays. The Bricks are designed to interface with signals typically used for substation automation and protection as close to their respective origins as practical, including AC currents and voltages from instrument transformers, breaker status and alarms, breaker control, disconnect switch status and control, temperature and pressure readings, and so on.

The Bricks are designed for harsh environments including temperature extremes, shock and vibration, electromagnetic compatibility, sun exposure, pressure washing and exposure to salt and other harsh chemicals.           
Each Brick contains four independent digital cores, each composed of a microcontroller with individual bi-directional (bi-di) fiber links. Each core provides dedicated point-to-point communications with a single relay using messages conforming to IEC 61850-8-1 (GOOSE) and IEC 61850-9-2 (Sampled Values). These cores share common input/output hardware, implementing a fail-safe hardware design strategy that ensures total isolation and independence of the digital cores.

For over 15 years, GE’s technical experts have been working intimately with IEEE, EPRI & IEC working groups to help define and develop standards for station bus communications. Beginning with UCA 2.0, GE was the first in the industry to embed and natively support the UCA 2.0 standard in the Multilin UR family of protection and control relays. Dedicated to the development of an open communications standard to enable substation automation and control at the station bus level, GE’s technical experts continued their work with the IEC working group to define the IEC 61850 standard protocol.
Through this effort GE was the first to embed IEC 61850 communications support within entire product platforms without the need of external protocol converters or other discrete devices. The latest in GE Digital Energy’s IEC 61850 developments include Metering with the EPM 7000 and EPM 9900 Revenue grade, High Accuracy, Power Quality meters. The EPM 7000 and 9900 are now IEC 61850 compatible provide advanced dual Ethernet communications functionality with simultaneous Modbus, DNP and IEC 61850 communications.

ABB recognized the demand for standardized interfaces early. Introducing microprocessor based protection caused in a lot of advantages regarding functionality, maintenance and operation. “Private” communication interfaces as well as measurement interfaces (for instance for non-conventional CTs and VTs) have not been accepted by the customers. So ABB joined the standardization working groups and took over editorial work in CIGRE and IEC WG10. Since interoperability was a main goal of IEC 61850 cooperation, tests and pilot projects with other vendors became essential. The OCIS project showed a setup with ABB, ALSTOM and SIEMENS in 1998 already. Further development was combined with the release of demonstration setups with other vendors. Some of these events have been mentioned in the last issue of the magazine already- Vancouver (2001), Dana Point (2002), and Ponte Vedra (2002).- all with SIEMENS and Omicron.
At the Hanover fair 2002 a demo system was presented, combined with a joint statement of ABB, ALSTOM and SIEMENS to deliver such systems beginning in 2004. Utilities as AEP (US), Terna (IT) and RWE (DE) explained the interest in using these systems when available.

At CIGRE in Paris (2002) an interoperability presentation was given. ABB delivered a compact switchgear PASS with sensors utilizing IEC 61850. The setup was extended for the 2004 CIGRE (Figure 5.)

Interoperability between merging units and protection IEDs has been certified between SIEMENS and ABB by KEMA in 2001 already- at this time for IEC 61850-9-1 utilizing point to point connections. As a pioneer in the fields of NCIT and process bus technology, ABB began commissioning a series of six outdoor substations with process bus and NCIT technology at Powerlink in Australia in 1999. 

Again intelligent plug-and-switch switch (iPASS) was used. Electronic modules integrated into the drives of the circuit breaker, disconnector and earthing switch of the iPASS modules could communicate using a proprietary optical process bus. Furthermore, the iPASS modules were equipped with ABB’s ELK-CP sensor for voltage and current measurement, also connected to the process bus.
The ELK-CP sensor families are based on redundant sets of Rogowski coils for current measurement and two independent capacitive dividers for voltage measurement.
As it contains no oil, this equipment is both environmentally friendly and extremely safe. The fully redundant design of the sensors (including the associated electronics) permits application of two completely independent and parallel protection systems, boosting the availability of the secondary system.

As sensor electronics can be replaced independently and without requiring a shutdown of the entire protection system, repair activities require less time and, because no live parts need to be handled, the activities are also much safer. ABB installed more than 300 such electronic sensors in Powerlink’s substations. Notably, in more than 10 years of service, none of the primary converters ever failed.  Powerlink launched an upgrade project that involved replacing secondary equipment in the hybrid substations, including the process-oriented electronics that connect to the process bus ten years later. A central requirement of this upgrade is its full compliance with international standards, especially the implementation of the process bus for sampled analog values, which has to comply with 9-2LE. 9-2LE is an implementation guideline of IEC 61850-9-2.  Powerlink awarded the contract for upgrading the first iPASS substation to ABB.

This project represents the world’s first commercial implementation of a process bus according to 9-2 LE. IEC 61850-9-2 requires that analog samples are transmitted by so-called merging units (MUs). The MU time correlates and merges analog data from individual phases or measuring points in the substation before transmitting them via the Ethernet network, from where the data can be accessed by protection and control devices. With the introduction of the CP-MUP, ABB was the first company to offer a conformance-tested, UCA-certified merging unit. (Figure 4)

The first HV substation was equipped with IEC 61850 in December 2004. One month after the first medium voltage substation (16-kV, Unterwerk Winznauschachen, November 2004 by SIEMENS- will be later covered) it was the challenging task to refurbish primary and secondary equipment in a 380 kV substation, also in Switzerland. The Elektrizitäts-Gesellschaft Laufenburg (EGL) operates an important part of the Swiss 380/220-kV-transmission system. The Laufenburg substation was put into operation in 1967. After almost 40 years of operation the equipment in 7 of 17 feeders was replaced within 2 years (Figure 6, Figure 8).

The parallel wires have been kept in operation at this time and a protocol converter to IEC 60870-5-101 was used.
In a typical IEC 61850 native design, the functionality of the IED must consider the entire process, including specification and evaluation, system and device engineering, system commissioning, and operations and maintenance. ABB’s Relion protection and control product family was one of the first to undergo the IEC 61850 transformation.
The products required a completely new platform architecture that would integrate communication services and data representation into the core protection and control applications. This development was carried out in parallel with the development of the IEC 61850 standard to ensure that the future ABB Relion family was designed from the beginning to support IEC 61850. The ABB new protection and control platform IED 670 is designed to utilize all aspects of the new standard and to be able to fulfil present and future demands.

To fulfil the IEC 61850 concept, especially with respect to engineering, it is necessary to fully implement the logical node concept etc, based on the 61850 standard.

A new concept for the numerical calculation module has been adapted. Instead of propriety CPU design, a commercially available processor has been selected.  The 670 IEDs have been introduced in 2007, coming up together with integrated engineering system PCM 600. Focusing on the distribution IEDs 615 and 630 have been released in 2009. (Figure 9)
The application of a waveguide system for IEC 61850 communication (utilizing 802.11a radio) was presented in 2008. The main application was in medium voltage switchgears.

IEC 61850 became the well accepted standard for power utility communication around the world. In 2007, China's first digital substation automation solution was put into operation with IEDs from SAC. In 2009, Guilin Substation 500KV, the first digital substation of China in compliance with IEC 61850 standard, was put into operation. Electronic transformers and other smart devices from SAC were integrated into the substation. In 2010, China's first 220KV intelligent substation was put into operation.

In Japan Toshiba contributed also to CIGRE 2004. Distance relay (GRZ100; Figure 10) with IEC 61850, a prototype, was demonstrated in Paris.
In the same year a prototype of Merging Unit and process bus based IED was available. Certification, GOOSE performance evaluation and another IOP presentation took place in 2006. After the first WAMPAC prototype system based on IEC 61850 in 2011 the GR200 series came out in 2012 and was part of the PRP redundancy IOP-presentation at CIGRE in the same year. Edition 2 devices are available since 2016 (Figure 12)

When IEC 61850-10 was released in 2005 conformance testing was described. Of course these activities started much earlier. UCA International IEC 61850 user group works on testing procedures. KEMA in the Netherlands (now DNV GL) with its Protocol Competence and Test Center was the first independent (level A) test organization authorized by the UCA Users Group to perform the official IEC 61850 conformance tests and issue UCA certificates. An early testing solution developed for CASM/GOMSFE (see last issue of the magazine) was UniCA (Figure 11; Figure 13)

Today several testing bodies are authorized by UCA Users Group. In August 2012, TÜV SÜD has been accredited by UCAIug as Level A Independent Test Lab (Figure 14).
Part 6 of IEC 61850 describes the engineering utilizing the Substation Configuration Language (SCL) and was published in 2004 for the first time. Of course in the first projects the vendors had to setup their IEDs working with their own system configurators being for instance a part of SIEMENS DIGSI or MiCOM Studio (both later covered). ABB used IET 600 (Integrated Engineering Tool) as powerful system configurator. Nevertheless more and more IEC 61850 engineering steps became possible in PCM 600 already (as mentioned- see above) in the years after. The vendor specific tools are recognized as “bottom-up”. The standard describes a “neutral” or “top-down” approach utilizing 3rd party tools. First solutions have been available quite early. Typical examples are SCT (H&S Figure 15 and Helinks Figure 16).

IEC 61850 does not describe communication with protection devices- it is about everything and so automation and control are important topics. The German company Eberle recognized early the advantages of interoperability and free configuration. As the first vendor of voltage regulators A. Eberle received the certificate for the REG-D controller in 2005. Further devices as Petersen-coil controllers REG-DP, Earth fault locator EOR-D, Power Quality devices PQI-D and collapse prediction relay CPR-D followed. All these devices can be equipped with protocol interface REG-PE and REG-PED making the IED capable for IEC 61850 communication. (Figure 17).

Another vendor of voltage controllers is MR (Maschinenfabrik Reinhausen). In February 2004 MR’s presentation of the TAPCON 240 voltage regulator with IEC 61850 protocol at the VDN Symposium in Jena (symposium of the German power network operators’ association) took place. Another highlight was MR’s delivery of 6 TAPCON 240 voltage regulators with control system connection to complement the substation control technology with IEC 61850 protocol realized by SIEMENS for RWE Power (Garzweiler opencast mine). This device came with a web interface to download the ICD-file from. Figure 18 shows a TAPCON 230 with IEC 61850 interface.

Real time digital simulators such as the RTDS Simulator are commonly used to perform closed-loop testing of power system protection and control devices including protective relays and integrated protection schemes. As the IEC 61850 communication protocol became more widely accepted and implemented, it was important that the testing tools keep pace allowing devices that adhere to the new standard to be properly tested.
When using IEC 61850, the electrical interfaces used for binary signaling and the voltage/current amplifiers associated with measured analogue signals can be replaced by an Ethernet connection and software. The RTDS Simulator’s IEC 61850 communication capability is provided by the GTNET or GTNETx2 card with the GTNET-SV and/or GTNET-GSE protocols installed. It was presented in 2010 (Figure 20). Client capabilities (“MMS Voyageur”) became available at the end of 2014.
Further testing aspects and vendors will be covered in the next issue of the magazine.

For finalizing this article we will consider a protection and control IED manufacturer from Austria- Sprecher Automation. Specialized on communication protocols they came with an interesting engineering approach for IEC 61850- to make the modelling independent and flexible.  The communication of their bay controllers could be adapted to customer’s needs and definitions (Figure 21).
For the application of GOOSE for protection purposes such as reverse blocking the fast GOOSE (P1 according to IEC61850-8-1 Edition 2.0 Table C.2) was implemented in the SPRECON devices in 2012. Figure 19 shows the setup for factory acceptance testing (FAT.)

walter.schossig@pacw.org        www.walter-schossig.de     

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