Combined Grid Solution inaugurated

20.10.2020

On 20 October, the world’s first hybrid offshore interconnector was ceremoniously put into operation: the Danish-German Combined Grid Solution (CGS). This interconnector in the Baltic Sea links the transmission grids of two countries via national offshore wind farm grid connections. For this purpose, two submarine cables with a length of merely 25 kilometres and a capacity of approx. 200MW each were laid between the offshore transformer platforms of the German wind farm Baltic 2 and the Kriegers Flak wind farm in the Danish part of the Baltic Sea, which is currently under construction. The CGS – a joint project of TSCNET shareholder 50Hertz, one of the four German transmission system operators (TSOs), and TSCNET customer Energinet, the TSO from Denmark – thus not only connects the platforms with each other but also the existing onshore connections of the wind farms. This allows the transmission of offshore wind power to Denmark or Germany and also cross-border electricity trading.

The official opening ceremony, which took place on site in the German capital of Berlin as well as digitally, was attended by Peter Altmaier, German Federal Minister for Economic Affairs and Energy, Dan Jørgensen, the Danish Minister for Climate, Energy and Utilities, as well as Kadri Simson, EU Commissioner for Energy. With their appearance, these high-ranking political representatives acknowledged the CGS as a technical innovation with model character for future offshore power grids. The hybrid nature of CGS is that it is the first electricity interconnector between two countries, that not only provides capacity for electricity trading, but also transports offshore wind energy onshore – in both directions. The costs of the binational EU-funded project amount to around €300m.

A technical obstacle had to be solved in the realisation of CGS: Because the transmission grids in eastern Denmark and Germany do not operate synchronously, it was necessary to install a back-to-back converter at the 50Hertz substation in Bentwisch near the port city of Rostock in the federal state of Mecklenburg-Western Pomerania. The device converts the incoming AC into DC and immediately back. Only in this way is it possible for electricity to flow smoothly from Denmark to Germany and vice versa. But CGS has not only hardware but also software components. The central digital control unit of the system is the Master Controller for Interconnector Operation (MIO), located in the 50Hertz control centre near Berlin. The MIO balances market requirements with offshore electricity production, which depends on wind conditions in the Baltic Sea. Its main function is to ensure optimum use of the CGS while preventing any overload of the line and the operating facilities in the substation.

Stefan Kapferer, CEO of 50Hertz, commented at the inauguration: “With this project, 50Hertz and Energinet are pioneering the efficient integration of offshore wind farms into the cross-border European electricity market. It offers us several effective options to balance the frequency and voltage of our transmission grids at all times, to deal with the integration of renewable energy sources with more flexibility and to increase the stability of the overall system.” Thomas Egebo, CEO of Energinet, added: “The CGS is not only a very important milestone in reaching Denmark’s ambitious goal of a 100 percent green power system in 2030. The groundbreaking project also delivers an important building block for decarbonising the rest of the society.”

The Danish-German Combined Grid Solution has been ceremoniously put into operation (illustration uses photos of 50Hertz, one of which shows Minister Altmeier)

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> See 50Hertz press release (html)
> See Energinet news release (html)
> Watch CGS inauguration film (YouTube)

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Huge Schnabel car for Amprion

08.10.2020

The grid expansion, that is necessary to create a sustainable energy future, entails many tasks for transmission system operators (TSOs), like planning procedures, overhead line construction, underground cable laying, upgrading and new construction of substations – and also, increasingly often, the transport of heavyweight transformers. To be able to carry out such transports in a plannable, flexible, and reliable manner and exactly at the time when it is needed for the implementation of important projects, the German TSO Amprion has now put its own Schnabel car into service. A Schnabel car is a special type of rail freight car designed to transport heavy and oversized loads. The load is suspended between the two ends of the Schnabel car by lifting arms to distribute the weight of the load evenly over many axles.

Amprion’s new transporting device is over 50 metres long, around 4.2 metres high, three metres wide and has 32 axles. When empty, it weighs 220 tonnes. In fact, it is the largest Schnabel car ever produced for the German market. The rolling heavyweight is capable of transporting all types of transformers that Amprion intends to install – including transformers and rotating phase shifters with a transport weight of up to 500 tonnes. The TSCNET shareholder is thinking long-term: The Schnabel car is to provide its service for a secure transmission system for the next 40 years.

On 6 October, the TSO was handed over the new Schnabel car at the heavy goods terminal in the Rhine city of Mannheim in Baden by the specialist company Kübler Heavy Rail. Hendrik Neumann, Amprion’s designated CTO, comments: “To implement the energy transition, we must adapt and expand our grid in such a way as to enable the integration of large quantities of renewably generated electricity.” For this, Amprion needs a large number of additional transformers and phase shifters, which the TSO can now transport across Germany with its new king-size Schnabel car.

Amprion has put its own Schnabel car for the rail transport of heavyweight transformers into service (picture with designated CTO Neumann on the right: Amprion / Raphael Foidl)

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> See Amprion press release, in German (html)

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€30m for secure electricity supply in East Tyrol

28.09.2020

Since autumn 2016, the Austrian transmission system operator (TSO) APG has been gradually renewing the 220kV switchgear at the Lienz substation in the eastern part of the Austrian state of Tyrol. The substation in Nußdorf-Debant near the medieval town of Lienz is of particular importance for the region’s electricity supply, as it is the only feed-in point from APG’s 380/220kV high-voltage grid for the whole of East Tyrol. For this reason, the TSCNET shareholder is pursuing an extensive investment programme of €30m for the substation to improve the electricity supply in East Tyrol and to enhance the integration of green electricity into the Austrian transmission grid.

The upgrade project also includes a new 380/220kV transformer. Due to its dimensions, it was transported by rail in three individual parts of 167 tonnes each from the Styrian Siemens plant in Weiz via an individual siding directly to the substation. Now the last part has arrived in Lienz and has been placed on its foundation. The total weight of the finished system is 816 tonnes. The state-of-the-art device will be operational from June 2021 and APG expects the upgrade of the entire substation to be completed in autumn 2022.

The Lienz transformer is of supra-regional relevance as it increases system security in all of Austria and also facilitates the country-wide use of climate-friendly wind energy. This is because the transformer strengthens the connection between the pumped storage power plants in the west of the country and the wind turbines in the east. With its investments, APG thus supports the national goal of covering 100% of the electricity consumption in Austria with green electricity by 2030. Company spokesperson Christoph Schuh comments: “All APG grid expansion, modernisation and maintenance projects are crucial for reaching Austria’s climate targets and indispensable cornerstones for guaranteeing the republic’s security of supply.”

APG is investing €30m in the upgrade of the Lienz substation in East Tyrol (picture: Michael Stabentheiner / APG)

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> See APG press release (html)

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TenneT installs first TCSC system in Germany

16.07.2020

Series compensation is an innovative technology that significantly increases voltage stability in transmission systems. The Dutch-German transmission system operator (TSO) TenneT is constructing Germany’s first series compensation system in the Stadorf substation in the Lüneburger Heath. From 2023, this will prevent grid bottlenecks in the German state of Lower Saxony. On 15 July 2020, the future heart of the upgraded substation reached Stadorf after an intricate transport by ship, rail and road and was placed on its foundation: a direct-coupling transformer with a transport weight of 528 tonnes.

The TSCNET shareholder supplies large areas of the eastern part of Lower Saxony with electricity via the Stadorf substation. Due to the energy transition and the corresponding transmission of wind power from the north of Germany to the consumption centres in the south, the substation will assume a supra-regional and important function in the future. For this purpose, Stadorf is being comprehensively modernised and extended by a so-called Thyristor Controlled Series Capacitor (TCSC) facility, the first of its kind in Germany.

TCSC allows a fast-dynamic modulation of the inserted reactance and in this case specifically to relieve persistently overloaded lines and redirect load flows. The new direct coupling transformer with a transmission capacity of 300MVA connects the 380kV lines of TenneT with the 110kV lines of the regional distribution system operator (DSO). It provides load flow in both directions, so that locally generated surplus green electricity can be transferred if required. As a result of the substation upgrade with TCSC equipment, the disconnection of wind turbines, regulatory intervention in the grid, and the associated costs will be reduced – and overall system security increased. TenneT anticipates annual savings in the double-digit million euro range.

TenneT is implementing a TCSC facility in the Stadorf substation, the first of its kind in Germany (picture: TenneT)

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> See TenneT press release, in German (html)

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Onshore converter for the Combined Grid Solution

31.01.2020

The Danish-German Combined Grid Solution (CGS) in the Baltic Sea is the world’s first offshore interconnector to use national grid connections of offshore wind farms to link the transmission systems of two countries. For this purpose, submarine cables were laid between the offshore transformer stations of the German wind farm Baltic 2 and the Kriegers Flak wind farm in the Danish part of the Baltic Sea. The CGS is a joint project of TSCNET shareholder 50Hertz, one of the four German transmission system operators (TSOs), and TSCNET customer Energinet, the TSO from Denmark.

The Bentwisch substation near the Baltic port city of Rostock houses the German onshore converters for the CGS. Here 50Hertz has installed a double converter system including a back-to-back converter. This is essential for balancing the asynchronous transmission systems of Germany and Eastern Denmark: The AC from the Nordic synchronous area is converted into DC and directly back into AC, now adapted to the European synchronous area.

50Hertz has now successively energised and commissioned all converter components in Bentwisch. The new equipment and further extensions of the substation had to be individually synchronised with the control technology in a series of individual testing and commissioning steps. The operational readiness of the double converter system in Bentwisch marks another important milestone on the way to the commissioning of the entire CGS.

The German onshore converter for the Danish-German offshore interconnector Combined Grid Solution has been commissioned by 50Hertz (picture: Jan Pauls / 50Hertz)

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> See 50Hertz project news (html)

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Swissgrid and hydropower storage plants agree on minimum production

20.12.2019

To avoid an overload of grid elements in western Switzerland during the winter holidays, TSCNET shareholder Swissgrid, the Swiss transmission system operator (TSO), has agreed upon a minimum production with selected regional hydropower storage plants. This is intended to reduce the potential increased and costly need for redispatch during these low-consumption days.

The measure is also necessary because the availability of the transformer at the Bassecourt substation in the canton of Jura is currently limited and the new transformer at Mühleberg in the canton of Berne has not yet been fully installed. Both projects will be implemented in spring 2020. The agreed minimum production in the period from 20 December 2019 to 6 January 2020 is 200MW (off-peak) and 400MW (peak).

Swissgrid has negotiated minimum production from hydropower storage plants

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> See Swissgrid news release (html)

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Two transformers reach Garenfeld

05.11.2019

The last weekend was literally “heavy” for TSCNET shareholder Amprion, one of the four German transmission system operators (TSOs). Not one but two 276-tonne transformers were transported to Amprion’s Garenfeld substation in Hagen in North Rhine-Westphalia. It took both days of the weekend for the 30 kilometre stretch from the railway station to the substation. The special road transport units each had a total length of around 80 metres and together with the transformer each weighed 519 tonnes.

About 40 employees from various companies were involved in the transport during the two nights. At the end of August, the first of a total of five transformers had already been delivered to the substation. Amprion is currently planning to move the last two transformers to Garenfeld at the end of November.

Two transformers have been delivered to the Garenfeld substation operated by Amprion (picture: Amprion)

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> See last week’s announcement press release, in German (html)
> See Amprion tweet, in German (html)

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Fauna-friendly extension of Amprion substations

25.07.2019

TSCNET shareholder Amprion, one of the four German transmission system operators (TSOs), is expanding its Siegburg substation in North Rhine-Westphalia, near the former seat of the West German government in Bonn. The planning is progressing well: By 2023, the existing 220/110kV substation is to be integrated into the 380kV grid. To this end, the current installations will be extended by a 380/220kV transformer and a gas-insulated switchgear at the 380kV voltage level. A new overhead line will connect the station to Amprion’s supra-regional transmission system.

But there is more to be told from Siegburg, as the substation provides a home for seven bee colonies. In May, further TSCNET shareholder TenneT, the Dutch-German TSO, reported on a pilot project on eco-friendly substation maintenance, and now Amprion also informs about new steps in this field: Around 350,000 bees of the Buckfast and the Carniolan breeds live in a specially fenced area and bring the nectar gathered on their flights back to the hives at the station. “We are very happy about our new neighbours,” says Klaus Breitbach, operations manager of the substation. “We hope that our new neighbours will thank us for the good location with one or the other glass of honey”.

News is also coming from the Bischoffsheim substation in the Rhine-Main Area. Here, too, Amprion is working on the grid of the future: To ensure security of supply for the region and the state capitals of Mainz (Rhineland-Palatinate) and Wiesbaden (Hesse), the TSO is expanding and modernising the existing 380kv system with a transformer and switch panels. On 27 July, Amprion expects the delivery of the 350MVA transformer. First, the transformer with a weight of around 350 tonnes is being transported by rail. The last 560 meters on the road will be taken over by a heavy haulage tractor unit with a length of 78 meters and two times twelve axles. The total weight of the transport unit is 574 tonnes.

Bees at Amprion substation

Amprion welcomes bee colonies to the Siegburg substation and is expecting a new transformer at the Bischoffsheim substation (picture: Amprion)

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> See Amprion press release on the Siegburg substation, in German (html)
> See Amprion press release on the Bischofsheim substation, in German (html)

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Transformer for TenneT’s hybrid Statcom facility

01.01.2019

Right on time for Christmas 2018, a heavy-duty train loaded with a 299-tonne transformer built by ABB reached the Borken substation operated by TSCNET shareholder TenneT, the Dutch-German transmission system operator (TSO). Here at the long-established substation site in Borken in the German state of Hesse, practically in the middle of the German power system, the TSO is currently building the first German hybrid static synchronous compensator system (Statcom). In order to efficiently connect the Statcom system, which will later be operated at 40kV, to the existing extra-high voltage grid, a so-called impedance matching transformer is required.

The hybrid Statcom facility will provide reactive power as compensation for the declining capacities previously provided by large power plants, which are now being successively taken off the grid in the course of the energy transition. In the three-phase transmission system, the reactive power must be in balance with the active power in order to maintain the grid’s voltage at the required level. That is why reactive power compensation is a priority task for the German TSOs.

On the morning of 8 January 2019, the foundations of the transformer will be laid in front of the Statcom plant which is currently under construction. It will then take around three months before the matching transformer is operational. The entire Statcom system is expected to be commissioned by the end of 2019. In Borken, TenneT is investing around €30m in future-proof grid operation. Germany’s first hybrid Statcom system will then not only contribute to dynamic voltage stabilisation, but the entire Borken substation will also become one of the most modern hubs for green power in the TenneT grid.

TenneT has been supplied with a matching HDVC transformer for its hybrid Statcom facility at the Borken substation (picture: ABB)

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> See TenneT press release, in German (html)

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New transformer for Laufenburg substation

20.11.2018

The Laufenburg substation in the Swiss canton of Aargau is not only one of the largest substations in Europe connecting the electrical systems of several countries, but also the birthplace of the European integrated network operation: In 1958, the “Star of Laufenburg” was put into operation as the first interconnection of the French, German and Swiss electricity grids. TSCNET shareholder Swissgrid is now upgrading the substation so that it can continue to guarantee regional and supraregional security of supply also in the future. With this upgrade, the Swiss transmission system operator (TSO) is implementing an important part of its grid modernisation and expansion plan, the so-called “Strategic Grid 2025”.

Already in 2017, the old 220kV outdoor switchgear in Laufenburg was replaced by a gas-insulated unit. The by now outdated transformer from 1966 is currently also being replaced, increasing the transformer capacity of the substation from 600MVA to 800MVA. The new 380/220kV transformer was manufactured in the Siemens plant in Weiz in the eastern part of the Austrian state of Styria and shipped from there to the Rhine port of Muttenz near Basel. The subsequent delivery of all individual parts of the device from the port to Laufenburg took around three weeks. The four poles of the transformer, each weighing about 200 tonnes, were moved individually on a special road transportation unit with twenty axes. At the same time, sixteen trucks brought additional material for the installation of the transformer to Laufenburg.

The new transformer will be installed with concrete walls surrounding each pole providing space for the connections of all poles, of which only three will be in operation simultaneously. Thanks to the installed connections, the reserve pole can be put into operation at short notice. Replacement of an active pole by a reserve pole is planned at five-year intervals, which will significantly increase the transformer’s lifespan. The commissioning of the new equipment is scheduled for mid-2019.

Swissgrid installs new 800MVA transformer at the Laufenburg substation in the canton of Aargau (picture: Swissgrid)

Linkup
> See Swissgrid news release (html)
> Watch video of the transport on Swissgrid’s YouTube channel (“Transport eines Giganten”, in German with English subtitles)

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