Cascade process of C/sells demonstrated successfully

25.10.2020

59 partners cooperate in the southern German smart grid project C/sells, including research institutions, distribution system operators (DSOs), municipal utilities, generators, service providers and consultants in the energy and IT sector – and the two TSCNET shareholders TransnetBW, the south-west German transmission system operator (TSO), and TenneT, the Dutch-German TSO. The aim of C/sells is to make the energy infrastructure renewable, decentralised, flexible, and participatory. The focus here is on the intelligent networking of generation and consumption and the use of innovative grid technologies and operating concepts. The “cell” is the basic unit of C/sells. It can be of a geographical nature, such as a city or district, or it can be a single object, such as an airport or even a single property. These “cells” assume a variety of functions and tasks that serve to stabilise the grid and provide flexibility. C/sells is funded by the German Federal Ministry for Economic Affairs and Energy in the framework of the innovation programme “Smart Energy Showcases” (“Schaufenster intelligente Energie” – SINTEG).

TransnetBW now reports a significant progress for C/sells, because together with the municipal utility of Schwäbisch Hall in the in the German state of Baden-Württemberg and the DSO Netze BW, the partially automated cascade process of C/sells was demonstrated live. A cascade process is usually understood as any process that takes place in a series of steps, and in this case, it is the step-by-step control of plants from downstream networks to remedy critical grid situations in an emergency. In the demonstration of 21 October, a simulated threat to system balancing was resolved by means of the partially automated cascade process and an intelligent measurement system. In the process, facilities were controlled right down to the lowest voltage level. The selected scenario was a realistic situation and required the cooperation of all grid operators.

The demonstration was based on the coordinated power grid cascade developed in C/sells which defines clear rules and processes for the respective grid operators. By means of control centre coupling, information on the state of the grid is continuously exchanged across all voltage levels. Several defined signal phases visualise the grid status in the control centres involved and indicate the measures to be derived from it. Thanks to the communication technology coupling of TransnetBW and Netze BW and the bidirectional exchange of information in real time, emergency situations can now be mastered jointly across voltage levels within just a few minutes. Dr. Rainer Enzenhöfer of TransnetBW and sub-project manager of C/sells comments on the successful demonstration: “With the partial automation of the cascade, it is possible, together with DSOs, to control a large number of decentralised plants in a simple and uncomplicated manner within a very short time in order to eliminate a critical grid situation.”

TransnetBW and its partners successfully demonstrated the cascade process of the C/sells smart grid project (picture: C/sells)

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> See TransnetBW press release, in German (html)
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Amprion commissions new Statcom facility

30.09.2020

The rising share of volatile renewable electricity generation and the increasing transmission distance from the places of generation to the centres of consumption require power grids to be adjusted, with immediate voltage regulation being a key element. To balance out voltage fluctuations, which are more and more occurring at the grid nodes, the European transmission system operators (TSOs) employ reactive power compensation systems. German TSCNET shareholder Amprion is no exception and already using a wide range of innovative technologies. On 29 September 2020, the company commissioned one more Statcom (static synchronous compensator) system, in this case on the site of the Kusenhorst substation in Haltern am See in the federal state of North Rhine-Westphalia. Almost exactly one year ago, Amprion commissioned an identical system at the Kriftel substation between Frankfurt and Wiesbaden in Hesse.

Amprion has invested a total of €37m in the expansion of the Kusenhorst substation. According to demand, the Statcom system can feed in reactive power in the range of about 300Mvar, thus raising or lowering the voltage in the grid to contribute to grid stability. The new Statcom can also be combined with the mechanical switched capacitor with damping network (MSCDN) already on site in Kusenhorst. Together, the two technologies form a so-called hybrid facility for reactive power compensation, making it the most powerful of its kind in the German grid alongside the Kriftel substation.

The Statcom system consists of several building sections, which are up to ten metres high and cover an area of approximately 1,000m². They contain the converter, chokes, and the regulation and protection technology. The transformer and the external cooler of the system are outside the buildings. Amprion operates the Statcom system remote-controlled via its system operation and control centre near Cologne.

Amprion has commissioned a Statcom system for reactive power at its Kusenhorst substation (picture: Amprion)

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> See Amprion press release, in German (html)

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Power outage in July in Valais cleared up

09.09.2020

As in many European countries, the Swiss transmission grid already today – at the beginning of the energy transition – has structural bottlenecks. Here, as elsewhere, these must be eliminated to increase security of supply and maintain it in the long term. Tense grid situations may pose problems to the connected system, as the Swiss transmission system operator (TSO) Swissgrid experienced on 17 July 2020, when the protection equipment of the 220kV grid node Creux de Chippis was accidentally tripped, which in the further course of events led to supply interruptions in the Valais distribution grid. The TSCNET shareholder immediately initiated extensive investigations into the event, the results of which have now been transparently communicated.

An extremely complex chain of technical and human factors is behind the Chippis incident. First the technical aspects: The transmission grid capacities in the region around Chippis are insufficient in summer due to the high generation of Alpine hydroelectric power plants. Because of this, Swissgrid for some time now had to completely disconnect the transmission grid in the Mörel substation in east-west direction for around 15 weeks a year to guarantee grid security and transmission capacities in the region. This reduces fault tolerance in the regional transmission system. In addition, several extension projects are currently being implemented in the Chippis area, which made adjustments to the operation of the Chippis substation necessary. These settings – also affecting the protection settings of the system – were carried out by the contracted service provider in December 2019.

As regards the human factor in the chain of events, necessary and scheduled tests of protection parameters were performed by a contracted specialised company in the Chippis substation on 17 July. During these tests, the system was not put into revision mode, which is why the system protection function unintentionally detected the test signal. This triggered the so-called busbar protection. The switchgear in the Chippis substation was subsequently disconnected and, due to the special grid situation, the switchgears in Stalden, Bitsch, Zermeiggern, and Mörel were also affected by the voltage loss, leading to a regional supply interruption in the distribution system.

The result of this combination of occurrences was a power failure in 60 municipalities in the district of Sierre and in most of the Upper Valais. After one hour, all affected switchgear and Swissgrid lines were back in regular operation. Thanks to the good cooperation between Swissgrid and the concerned distribution system operators (DSOs) of the lower voltage levels, electricity supply was gradually resumed and after less than two hours, almost all customers were back on power. Adrian Häsler, Head of Grid Infrastructure at Swissgrid, classifies she supply disruption in Valais as “an extremely rare occurrence”, but nevertheless apologises to those affected. And though the tests themselves were not negligent, the findings from the incident are incorporated into the company’s training and education of internal and external experts. Häsler also emphasises that Swissgrid drew attention to the bottlenecks in Valais some time ago: “Incidentally, we recognised these grid congestion problems in the context of ‘Strategic Grid 2025’, the TSO’s ambitious grid modernisation and extension plan, and addressed them in 2015. The grid expansion as planned by Swissgrid is essential to maintain the long-term security of supply.”

Swissgrid is investigating the voltage loss in the switchgear of the Chippis substation in Valais on 17 July (picture: Swissgrid)

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> See Swissgrid media release (html)
> See Swissgrid blog post (html)

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Successful trial run for Equigy

09.09.2020

Fluctuations in the transmission grid are an emerging concern for European transmission system operators (TSOs) as volatile renewable generation gains in importance with the energy transition and more and more large scale power plants that stabilise the grid are being decommissioned – resulting in a considerable loss of reactive power. TSOs need to take remedial action involving intelligent technologies and supported by small, decentralised energy sources to keep production and consumption in balance. One such solution for the provision of primary control energy is the crowd balancing platform Equigy launched by the Swiss TSCNET shareholder Swissgrid in cooperation with further TSCNET shareholder TenneT, the Dutch-German TSO, and the Italian TSO Terna.

Kick-off for Equigy was in April 2020 and the objective is a new European standard allowing the participating – and possibly more – TSOs to collaborate for promotion and improvement of the renewable energy market. The innovative platform is based on blockchain technology and the Internet of Things to enable the integration of small, decentralised units such as home battery storage systems, photovoltaic systems, small-scale hydropower systems, heat pumps or even electric cars into the balancing energy market. The pilot project now has reached its first milestone: Together with Alpiq, a Swiss energy services provider and electricity producer, Swissgrid has successfully tested the process of calling up primary control power through the balancing platform. The test employed a 1.2MW battery as a flexible energy resource. Alpiq has assumed the role of commercial aggregator, linking the technical aggregator, which controls the controllable resources, with Swissgrid.

In particular, the call-up of primary control energy included the registration of flexible resources, submission of offers and awarding of bids, as well as real-time monitoring of data exchange between Alpiq and Swissgrid. The test has proven that a blockchain can support the process of providing primary control power and that aggregators or storage owners with backend systems can integrate the blockchain interfaces. The Equigy trial run has clearly indicated the potential of blockchain solutions for the future support of business processes in the field of primary control energy – this is a fundamental finding and a significant step forward. The next steps concern the evaluation of possible business models among the participating partners.

The blockchain-based crowd balancing platform Equigy by Swissgrid, TenneT, and Terna passed trial run

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> See Swissgrid news release (html)
> Visit Equigy website (html)

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Amprion: “Smart Valve” for flexible power flow control

05.08.2020

To maintain the stability of the transmission grid despite the current increase in decentralised and volatile generation, the German transmission system operator (TSO) Amprion – like many other TSCNET shareholders – is already using a wide range of innovative technologies, for instance Phase-shifting transformers (PSTs) or reactive power compensation systems such as Statcom. A promising pilot project has now additionally been launched, for which Amprion has signed a cooperation agreement with the US Silicon Valley company, Smart Wires. In the three-phase project, the mobile modular static-synchronous series compensator (mSSSC) developed by Smart Wires, the so called SmartValve, will be deployed in the Amprion grid.

The aim of the project is both to increase the transmission capacity of Amprion’s transmission grid and to maintain its high level of system stability. SmartValve is designed for a more balanced and thus more efficient use of power lines. By actively changing the power flows, it enables better control of the transmission system and minimises redispatch. Due to its modular structure, SmartValve is easy to transport and can be operated flexibly at different locations. This distinguishes the new technology from conventional PSTs, for example, making it an ideal complement to support the system from a stability perspective.

Dr. Klaus Kleinekorte, CTO at Amprion, refers in this context to the significantly increased costs for redispatch in Germany in recent years due to the changes in the energy landscape. This is where the SmartValve project comes in: “We see this innovative technology as having the potential to allow us to use the network more efficiently and reduce the need for redispatch.” The two partners expect the project to span two to three years to verify the added value of the new technology in the Amprion grid.

Amprion and Smart Wires launched a pilot project to implement the SmartValve solution in the transmission grid (picture: Smart Wires)

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Swissgrid analyses supply disruption in Valais

22.07.2020

On Friday, 17 July, the Swiss transmission system operator (TSO) Swissgrid carried out check-operations concerning the extension of the 220kV switchgear in the Chippis substation in the canton of Valais. At 4.23 p.m., the protection equipment of the 220kV grid node Creux de Chippis was accidentally tripped, causing the switchgear to lose voltage. As a result of the technical failure at Chippis, the switchgear of the substations in Stalden, Bitsch, and Mörel were also affected by the voltage drop, which led to a regional supply interruption in the distribution system.

The result was a one-hour power outage in a total of 60 municipalities with around 112,000 households as well as trade and industry in the Swiss Sierre district and the largest part of the Upper Valais. By 5.23 p.m., all affected switchgear and lines of the TSCNET shareholder were back in regular operation. Thanks to the good cooperation between Swissgrid and the five affected distribution system operators (DSOs) of the lower voltage levels, it was possible to gradually restore the electricity supply from 5 pm onwards. By 6.15p.m. almost all customers were back on power. Swissgrid immediately initiated a detailed investigation of the incident, which is currently in progress.

Swissgrid is investigating the voltage loss in the switchgear of the Chippis substation in Valais on 17 July (picture: Swissgrid)

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> See Swissgrid news release, in German (html)

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Worldwide unique equipment for TransnetBW substation

18.07.2020

European transmission system operators (TSOs) respond to the increasing need for grid regulation – resulting from the growing share of volatile renewable energies and the proceeding shutdown of conventional power plants – with reactive power compensation measures, such as the installation of shunt reactors. Shunt reactors are absorbers of reactive power and support security of supply and system management by keeping the grid voltage within the specified range, especially during low load periods. They thus stabilise the power grids and increase the energy efficiency of the transmission system.

In the Stuttgart-Mühlhausen substation, TransnetBW, one of the four German TSOs, has commissioned a variable shunt reactor for reactive power compensation developed especially for the TSCNET shareholder. Up to now in the TransnetBW control area, shunt reactors have only been used in the 110kV grid. Compared to customary reactors, the new system provides a much more precise control of the grid voltage. The 360-tonne reactor has a control bandwidth of 50-250MVAr in 33 stages and a permanently permissible system voltage of 440kV. With these specifications, the Mühlhausen shunt reactor is not only a novelty for TransnetBW, but for the entire energy sector.

TransnetBW has commissioned a state-of-the-art shunt reactor in the Stuttgart-Mühlhausen substation (symbolic picture: Siemens)

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Construction permit for Pradella-La Punt

13.07.2020

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)

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Smart control of heat pumps – HeatFlex expands

08.07.2020

Launched in the summer of 2018, the HeatFlex research project aims to exploit the potential for grid stabilisation that small and decentralised consumer devices can offer – if actively involved in the stabilising process. The founding project members are TSCNET shareholder TenneT, the Dutch-German transmission system operator (TSO), and the southern German distribution system operator (DSO) Bayernwerk Netz. Following the successful cooperation and positive test results, TenneT and Bayernwerk Netz are now expanding the project. The grid operators are pleased to welcome three new project partners: the DSO Regensburg Netz as well as the public utilities Stadtwerk Haßfurt and SWW Wunsiedel.

With HeatFlex, TenneT and Bayernwerk are jointly researching the most effective integration of decentralised devices – such as electric storage heaters, heat pumps, and water heaters – into grid balancing. These flexible capacities are intended to avoid cost-intensive interventions by the TSO in the case of future grid bottlenecks. Since November 2019, the project partners have already been implementing the first concrete measures based on HeatFlex results: The heat pumps and direct heating systems connected to Bayernwerk Netz are being intelligently controlled for bottleneck prevention. Decentralised heating systems are thus partially taking over the stabilising function of fossil plants. Using ripple control technology already in place, no additional investments are required.

The increase in partners should serve to make intelligent use of even more local flexibility and to investigate further controllable, decentralised consumption units and alternative applications. The ultimate aims of HeatFlex are cost savings, reduction of grid extension, and the acceleration of the energy transition without jeopardising system security. “The intelligent control of the smallest, decentralised electricity consumption units is a small but essential element,” explains TenneT Managing Director Tim Meyerjürgens, “because the many pieces of the puzzle together make up the overall picture of the energy transition”.

The research project HeatFlex is extended with three additional partners (picture: Stiebel Eltron)

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> See TenneT press release, in German (html)

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SVC for SINCRO.GRID in Konjsko

02.07.2020

As in many parts of Europe, the increasing integration of decentralised, volatile renewable energy sources has also led in Croatia and Slovenia to a lack of flexibility and reactive power. The two TSCNET shareholders HOPS, the transmission system operator (TSO) from Croatia, and ELES, the Slovenian TSO, react to this with their joint project SINCRO.GRID that also involves two distribution system operators (DSOs) from the respective countries. The European Project of Common Interest (PCI) aims to optimise the efficiency of the two national electricity transmission networks through advanced technologies and innovative data processing methods. These include compensation devices, a dynamic thermal rating system, a battery power storage system, and a virtual cross-border control centre.

The start of construction of a static VAR compensator (SVC) in the Dalmatian substation in Konjsko on 30 June represents another significant milestone in the implementation of SINCRO.GRID. This state-of-the-art compensation system will support HOPS in actively controlling the reactive power flows in the Croatian power grid. The ceremony to mark the construction start was attended by high-ranking representatives of the Croatian government and the energy companies involved.

In addition to the SVC in Konjsko, SINCRO.GRID comprises three further main elements in Croatia: a variable shunt reactor (VSR) in the Mraclin substation near Zagreb, which was commissioned in January 2020, another VSR in the Melina substation, which is scheduled to be commissioned at the end of 2020, and finally a joint Croatian-Slovenian virtual control centre. Tomislav Plavšić, President of the HOPS Management Board, describes the latter as a unique solution for coordinated voltage regulation on the entire territory of both countries. The principal task of the binational virtual centre is to integrate three devices each in Croatia and Slovenia for reactive power compensation into one common operation to fully exploit their synergy potential.

HOPS has commenced construction of a SVC as part of the SINCRO.GRID project in Konjsko (picture with Tomislav Plavšić in the foreground: HOPS)

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> See HOPS press release, in Croatian (html)
> Visit SINCRO.GRID website (html)

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