Way is paved for 400kV line in western Romania


For more than ten years, the completion of the 400kV Oradea-Békéscsaba overhead line in the far west of Romania has been prevented due to unresolved ownership issues regarding the section Oradea South-Nădab. Because of this, the line could only partially be put into operation, that is between the Romanian town Nădab and the Hungarian town Békéscsaba, near the Romanian-Hungarian border. Now the property situation has been clarified and the Romanian transmission system operator (TSO) and TSCNET shareholder Transelectrica was able to award the building contract for the missing section.

Transelectrica expects the construction work to be completed within twelve months. The commissioning of the last 72-kilometre section and thus the completion of the Oradea-Békéscsaba overhead line will contribute to the closure of the “400kV Ring” in the west of Romania. This project is a priority energy target for Romania, which will significantly improve the operational reliability of the national transmission system and security of electricity supply in the north-west of the country. The new Oradea-Békéscsaba line will also enable Transelectrica to eliminate congestions and thus save considerable costs for grid interventions. Finally, Romania’s interconnection capacity will be increased by 100MW in export and 300MW in import direction, which will not only contribute to compliance with EU regulations, but also make a sustainable contribution to the integration of the European electricity market.

Transelectrica has awarded the building contracts for the last section of the 400kV Oradea-Békéscsaba overhead line (picture of Oradea: Marculescu Eugen Iancu, Creative Commons)

> See Transelectrica press release, in Romanian (pdf, 191.kb)

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Construction permit for Pradella-La Punt


As the extra-high voltage line in the Swiss Engadine between Pradella and La Punt constitutes a bottleneck in the Swiss and pan-European transmission system, the Swiss transmission system operator (TSO) Swissgrid has long aimed to increase its transmission capacity to 2 x 380kV. This will improve import capacity and security of supply in the canton of Graubünden and facilitate the transport of Engadine hydropower. The project is part of the “Strategic Grid 2025”, Swissgrid’s ambitious modernisation and expansion plan.

The Swiss Federal Inspectorate for Heavy Current Installations (Eidgenössisches Starkstrominspektorat-ESTI) now has approved the reinforcement and new construction of pylons between Pradella and La Punt. Swissgrid has already refurbished the pylon foundations in the past two years, so that work can commence soon. Approximately 3500 tonnes of steel will be needed to upgrade the around 50-kilometre-long overhead line. The construction will be carried out in two sections and is expected to be completed by the end of 2022.

To reduce the overall environmental impact in the region, Swissgrid is supporting a local grid operator in replacing a 60kV overhead line with a 110kV underground cable. As a result, 1100 pylons will be disappearing from the landscape.

Swissgrid can start with the 2 x 380kV upgrade of the Pradella-La Punt line (picture: Swissgrid)

> See Swissgrid media release (html)

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High-voltage pylon of Swissgrid sabotaged


On the morning of Friday 26 June, motorists on the Lausanne-Geneva motorway near the municipality of Gland in the Swiss canton of Vaud noticed how a high-voltage pylon collapsed. The cantonal police of Vaud were alerted and immediately cordoned off the area around the scene. No persons were injured. TSCNET shareholder Swissgrid, the Swiss transmission system operator (TSO), disconnected and grounded the two 220kV lines affected by the collapse of the pylon, Banlieue Ouest-Foretaille and Crans-Romanel. Grid stability is guaranteed and there are no supply failures in the Swiss transmission system.

Initial findings indicate that the pylon was subject to an act of sabotage, probably with the help of explosives. On-site investigations have been carried out by the Vaud Cantonal Police and the Swiss Federal Office of Police (Fedpol) while a criminal investigation has been opened by the Office of the Attorney General of Switzerland.

A 220kV pylon of Swissgrid has collapsed after an act of sabotage (picture: Canton de Vaud)

> See Swissgrid news release, in German (html)
> See Media release of the Cantonal Police of Vaud, in French (html)

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Work begins on the final section of Nant de Drance


The Nant de Drance pumped storage power plant in the Swiss canton of Valais is being commissioned successively in sections since 2019. The plant has a capacity of 900MW, making it one of the most powerful pumped storage plants in Europe – when it is fully operational in 2021, it will be able to generate close to 2.5bn KWh a year. TSCNET shareholder Swissgrid, the Swiss transmission system operator (TSO), is responsible for connecting the power plant to the extra-high voltage grid and for to transmitting the hydropower to the urban areas of Switzerland.

Swissgrid is implementing the 380kV connection in three sections, two of which were already commissioned at the end of November 2018: the 6.5km underground cable line connecting the Nant de Drance power plant to the Châtelard substation via the plant’s access tunnel, and the 12.5km overhead line between the Châtelard and La Bâtiaz substations. The last section – from La Bâtiaz to the connecting point to the Chamoson-Romanel overhead line in Le Verney – crosses the Rhône valley over a length of 1.3km. An underground variant for this section was finally approved in January 2020 by the Federal Inspectorate for Heavy Current Installations (“Eidgenössisches Starkstrominspektorat”, ESTI). It provides for a tunnel with a diameter of around 2.5m and a depth of 12 to 20m to be drilled between different groundwater levels. This is the second underground extra-high voltage line built by Swissgrid, but the first to extend at great depth for more than one kilometre.

Preparations for construction work on the two sites in Le Verney and La Bâtiaz have been underway since mid-May. Excavation of the shafts at Le Verney will commence in mid-June. In August, the mini tunnel boring machine will be installed on the main construction site in Le Verney. Tunnel driving will take about eight months and start in September 2020 at the same time as the excavation of the shafts in La Bâtiaz. After around two years of work, the third section is scheduled to be commissioned, until which time a provisional solution has been found: In 2019, the voltage of one of the two overhead lines La Bâtiaz – Le Rosel was increased to 380kV.

Swissgrid is starting construction of the final section of the connection of Nant de Drance to the national 380kV grid (picture: Nant de Drance SA)

> See Swissgrid news release (html)

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New 380kV line Airolo-Lavorgo in approval phase


The first plans to increase the transmission capacity of the overhead lines in the Leventina Valley in the Swiss canton of Ticino date back to 1997. Today, the upgrade of the 23-kilometre-long line between the Airolo and Lavorgo substations from 220kV to 380kV is part of the “Strategic Grid 2025”, the infrastructure expansion plan of the Swiss transmission system operator (TSO) Swissgrid. This is a future-oriented measure of ecological value, because the TSCNET shareholder is not only enhancing capacity and security of supply for Ticino and the whole of Switzerland, but thanks to the new overhead line and the subsequent upgrade of the lines in the Maggia Valley, the hydroelectric power plants in Ticino will no longer be subject to output restrictions.

The planning corridor was approved by the Swiss Federal Council in March 2016, which provides for the line to run along the western bank of the Ticino River, which flows through the Leventina Valley. Based on this decision, Swissgrid – in close cooperation with the Canton of Ticino, municipalities and citizens’ communities – has designed the final routing, which has now been submitted for approval to the Swiss Federal Inspectorate for Heavy Current Installations (“Eidgenössisches Starkstrominspektorat”, ESTI).

The Airolo-Lavorgo line complements the connection under construction between Chippis in Valais and Lavorgo and secures the electricity supply of Ticino with an additional 380kV system. According to the plans now submitted to ESTI, the new route of the line in the Leventina Valley is to run far from any residential areas. Once the new line is operational, the current 220kV line, which in comparison is much closer to settlements, can be dismantled. The completion of the new lines in both the Leventina and the Maggia Valley, scheduled for 2035, will, under current planning, ultimately enable the disassembly of more than 60 kilometres of overhead lines.

Swissgrid has submitted the application for building the 380kV line Airolo-Lavorgo (picture: Swissgrid) 

> See Swissgrid media release (html)

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380kV line Beznau-Birr commissioned ahead of schedule


The upgrading of the existing 220kV line between Beznau in the canton of Aargau and Mettlen in the canton of Lucerne to 380kV is a key component of the “Strategic Grid 2025“, the national expansion plan for the transmission infrastructure of the Swiss transmission system operator (TSO) Swissgrid. The voltage increase ensures energy distribution and supply security in the Zurich metropolitan area, Central Switzerland, and the Swiss Central Plateau. The TSCNET shareholder has now put the first section between Beznau and Birr in Aargau into operation, one year earlier than planned.

This stretch was partly installed underground, namely across the so-called Gäbihübel near Bözberg/Riniken about halfway between Beznau and Birr. The cable laying at the Gäbihübel is the first time that part of an extra-high voltage line in Switzerland has been implemented using underground cables. Twelve cables with a weight of 30 tonnes each were installed in the conduit blocks in the summer of 2019. This was followed by the completion of the overhead line section. To connect overhead lines and underground cables, special structures were erected at both ends of the approximately 1.3-kilometre-long underground section. After a construction period of around two years, the Swissgrid control centre connected the new 380kV line to the transmission grid on 19 May 2020. The reasons for the early completion were Swissgrid’s successful project and implementation planning as well as the rather warm and dry weather.

Swissgrid is providing scientific support for the construction, commissioning, and further operation of the underground cable. Investigations are carried out, for example, on the thermal behaviour of the cable conductors depending on the current load, the temperature variation in the soil above the conduit block and in the surroundings, and the biodiversity in the soil. In May, work began on dismantling the old 220kV overhead line and restoration of the pylon sites to their original condition. The deconstruction work is expected to last until the end of 2020.

Swissgrid has put into operation the 380kV line Beznau-Birr, the first Swiss extra-high voltage line partially laid underground (picture: Swissgrid)

> See Swissgrid media release (html)

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First section of new 50Hertz 380kV line in operation


The 37-kilometre line section between the Stendal West and Wolmirstedt substations in the German state of Saxony-Anhalt is the southernmost stretch of an overhead line construction project, which runs for a total of over 200 kilometres from Güstrow in Mecklenburg-Western Pomerania to Wolmirstedt. With this 380kV line construction, TSCNET shareholder 50Hertz, the transmission system operator (TSO) from north-east of Germany, is successively replacing a 220kV line dating from the 50s of the last century. On 12 May, 50Hertz commissioned the Stendal West-Wolmirstedt section, whose construction costs amounted to around €40m.

In May 2019, the TSO had started erecting the 87 Pylons of this first stretch of the new transmission line, which could be installed along the entire length of the section parallel to an existing 380kv line. This continuous line bundling follows the 50Hertz planning principle of using existing infrastructure wherever possible. After the conclusion of the approval procedures, construction, and commissioning of all six sections towards Güstrow, 50Hertz will completely dismantle the old 220kV line Güstrow-Wolmirstedt.

The main objective of the 50 Hertz construction project is to improve the transmission capacity for wind power. Dr. Frank Golletz, CTO of 50Hertz, comments on the progress of the extra-high voltage line: “The increase in transmission capacity is necessary to enable us to better manage the high volume of wind energy in the northern regions of our control area and to integrate it securely into our grid. With the commissioning of this first construction phase, we have come a step closer to this target.”

50Hertz has commissioned the new 380kV overhead line between Stendal West and Wolmirstedt (picture: City of Stendal, Germany)

> See 50Hertz press release, in German (html)

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Minor power failure, major solution


Only 16 minutes long was the power outage, and it affected only part of the state of Salzburg, but for the Austrian transmission system operator (TSO) APG, the small event was nevertheless related to a much bigger project. The Salzburg Line (“Salzburgleitung”) is a 380kv overhead line project of the TSCNET shareholder. The aim is not only to integrate increasing amounts of renewable energy into the grid, but also to ensure the long-term security of electricity supply for the Salzburg region and the whole of Austria. The line is a key factor in meeting #mission2030, the Austrian energy and climate strategy, which sets the national goal of covering 100% of electricity consumption with renewable energies by 2030.

The current incident has unexpectedly confirmed the necessity of building a new transmission line: Due to a technical defect, the grid coupling of the APG high-voltage grid at the Kaprun substation to the 110kV grid of Salzburg was interrupted, which led to a power outage. Thanks to the swift action of the APG experts, the connection was restored after only a good quarter of an hour. The incident had no critical consequences, but it clearly shows how important additional grid support for the Salzburg distribution grid through the new 380kV line and the new Pongau substation is.

A short-term power outage in the Austrian state of Salzburg underscored the importance of the planned Salzburg Line for grid stability (edited picture of Bruck near Kaprun: Kassandro, Creative Commons)

> See APG press release, in German (html)

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New Rhône Valley power line operational in 2022


In early 2018, TSCNET shareholder Swissgrid, the Swiss transmission system operator (TSO), began preparations for the construction of the new 380kV line in the Rhône Valley between the two substations Chamoson and Chippis, which is to replace the old 220kV line. This new line is of crucial importance for Switzerland’s security of supply, particularly for the transmission of electricity generated in the Valais hydroelectric power plants to the consumption centres in the central Swiss Plateau.

After about 18 months of actual construction, the extra-high voltage line is now taking shape and work is underway along its entire length. But not only do numerous safety measures have to be considered during construction, also the access to some plots of land has not yet been clarified at some pylon sites. These locations are distributed along the entire route of the line. As a decision by the responsible federal authorities is still pending in some cases, Swissgrid has now reviewed the construction plans and postponed commissioning of the new line until summer 2022. As the Federal Evaluation Commission (“Eidgenössische Schätzungskommission”) has given priority to the TSO’s applications, Swissgrid is confident about the further construction of the line.

Swissgrid expects the new 380kV line from Chamoson to Chippis to be commissioned in summer 2022 (picture: Swissgrid)

> See Swissgrid news release, in German (html)

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TransnetBW promotes weather-dependent line operation


The energy transition requires the transport of increased amounts of electricity and thus more efficient grid usage. TransnetBW, the transmission system operator (TSO) from the southwest of Germany, intends to take greater account of the fact that overhead lines have different maximum loads depending on the weather conditions. On a cool, windy day, for instance, considerably more electricity can be transported than on a hot, windless day. To make optimum use of this effect, the TSCNET shareholder is currently implementing a system that provides the necessary detailed information about the specific line capacity for improved network management.

The project, which the TSO is carrying out together with Energy & Meteo Systems GmbH, a provider of power predictions and virtual power plants, is called “Witterungsabhängiger Freileitungsbetrieb 3.0” (weather-dependent overhead line operation 3.0 – WAFB 3.0). Together, significant locations for the real-time monitoring of overhead lines in the TransnetBW control area were defined and weather stations and sensors are now being installed at 250 pylons and 48 substations to detect the weather-dependent transmission capacity of the respective lines. This will give TransnetBW much more accurate data on the utilisation of the grid to better avoid bottlenecks.

Alexander Hofmann, WAFB 3.0 project manager at TransnetBW, explains the approach: “Up to now, we have only considered the temperature at regional level for our grid operation. With WAFB 3.0, we record not only the temperature but also the wind on a small scale, which opens up much more options for our daily grid operation. Initially, the system helps us to check the forecast values used and to adjust them if necessary. From 2023 on, it will determine for each line individually and in real time which transmission capacities will be available when required.”

TransnetBW collects and utilises data on the weather-dependent transmission capacity of overhead lines (picture: analogicus)

> See TransnetBW press release, in German (html)

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