Agreement on synchronous interconnection

01.06.2019

There are five synchronous electricity areas in Europe: Continental Europe (CE), Nordic, Baltic, British and finally the area of Ireland and Northern Ireland. The CE area with the synchronised transmission grids of 26 countries is not only the largest in Europe, but also one of the largest interconnected power systems worldwide. The synchronisation of the Baltic area with CE is of strategic importance for the European Energy Union, one of the political priorities of the European Commission. Currently, the Baltic system is only asynchronously linked to CE between Lithuania and Poland through the “LitPol Link” and at two points to the Nordic region.

An application for a future synchronisation of the Baltic and CE systems was made by the three Baltic transmission system operators (TSOs) Elering, AST and Litgrid with support from TSCNET shareholder PSE, the Polish TSO. The European Network of Transmission System Operators (ENTSO-E) has now announced the first landmark for the project: An agreement on the conditions for a synchronous interconnection became effective on 27 May 2019. Synchronisation will enable the Baltic TSOs to operate their systems in the future at the same frequency as the CE system and in compliance with EU rules.

An agreement on the conditions for synchronous interconnection of the Baltic and CE energy systems has entered into force (picture of Riga by Aleksejs Bergmanis / Pixabay)

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> See ENTSO-E press release (html)

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ENTSO-E report on frequency drop

29.05.2019

On Thursday, 10 January 2019, shortly after 9 p.m., a deviation from the 50Hz mid-frequency was registered in the Continental European (CE) power system, which comprises the synchronised transmission grids of 26 countries. The deviation lasted 9 seconds and, with a drop to 49.808Hz, was the largest absolute frequency deviation since the so-called “European Blackout 2006”, when the frequency reached 49.0Hz.

Thanks to immediate collective action by the transmission system operators (TSOs) of the CE Regional Group the underfrequency was quickly rectified and the European security of supply was not compromised at any moment. In concrete terms, the activation of CE reserves and of interruptible contracts with French industrial customers returned the situation to normal. To identify the root causes of the incident, the European Network of Transmission System Operators for Electricity (ENTSO-E) undertook in-depth investigations and has now released a detailed and transparent technical analysis.

According to this report, the large drop was caused by the superposition of two factors. A significant deterministic frequency deviation (DFD) during the evening peak load encountered another, unpredicted one, registered between 9 and 11 January and caused by a technical error resulting from a frozen measurement on four connecting lines between Austria and Germany. The cumulative effect of the permanent frequency deviation from 9 to 11 January and the significant evening DFD on 10 January led to the frequency loss in the interconnected CE system.

The ENTSO-E technical report indicates that solutions for DFDs in the CE region need to be found. DFDs have been observed for years, but are now becoming more common and are of greater amplitude due to imbalances between generation and demand. Possible solutions to DFDs may require a change in operating and/or market rules. ENTSO-E will make further enquiries in close dialogue with all interested parties.

ENTSO-E has released an in-depth report on the frequency drop in the CE power system from January 2019 (illustration: ENTSO-E)

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> Open ENTSO-E report (pdf, 2.65Mb)

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APG and ENTSO-E comment on frequency drop

16.01.2019

Last Thursday, 10 January 2019, at around 9 p.m., a deviation from the 50Hz mid-frequency to 49.8Hz was registered in the Continental European (CE) Power System which comprises the synchronised transmission grids of 25 countries. As foreseen in such cases, immediate collective actions have been taken by the transmission system operators (TSOs) of the CE Regional Group and the underfrequency was rectified within a few seconds. The incident was clearly sufficient to alert the TSOs, but at no time did it jeopardise the European security of supply.

Nevertheless, there have been reports in some Austrian media about a potential interruption of the European electricity supply, comparable to the event of November 2006, when ten million households in France were disconnected from the grid as a precautionary measure. These press reports have provoked reactions from TSCNET shareholder APG, the Austrian TSO, and the European Network of Transmission System Operators for Electricity (ENTSO-E), who both stated that the comprehensive technical analysis is still pending but that there was no risk of a major power failure at any time.

APG has already made initial statements on the incident. According to APG, the cause was most likely a combination of several circumstances, but the decisive factor was probably a data error at another TSO at a transfer point on the Austro-German border. This occurrence could not be compared with that of 2006, when line overload was the reason.

APG and ENTSO-E respond to press reports on the frequency drop in the CE power system and confirm permanent security of supply

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> See APG press release, in German (html)
> See ENTSO-E press release (html)

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TSOs support ENTSO-E to prevent frequency deviations

13.11.2018

The Continental European (CE) Power System which comprises the synchronised transmission grids of 25 countries has been subject to occasional deviations from the 50Hz mid-frequency since late 2017. Each time the deviations originated from the Serbia, Macedonia, Montenegro (SMM) control block, specifically from the control areas of Kosovo and Serbia – an example of how a regional conflict in an interconnected system can have pan-European impacts. The European Network of Transmission System Operators for Electricity (ENTSO-E) has consistently undertaken efforts to find a political solution to the problem, and the CE transmission system operators (TSOs) have pledged their support in addition to the technical measures they are implementing anyway to limit the deviations.

Obviously, the problem is not only an issue for ENTSO-E and its members, but also of interest to the general public. It needs to be solved in order to keep the system consistently stable, to avoid further time deviations in electronically controlled watches, to limit financial effects, and ultimately to avoid a potential blackout in Europe. Considering the next winter period, this should happen in the short term. ENTSO-E is therefore in close and continuous exchange with the two responsible TSOs, EMS from Serbia and KOSTT from Kosovo, and has the task of facilitating a solution between the TSOs.

ENTSO-E’s Regional Group CE, which represents all transmission system operators of the 25 countries in the CE synchronous area, voted last week on a proposal to put an end to the deviations. The suggestion aims to provide a basis for a transitional solution and does not impose a principle on either of the two TSOs. ENTSO-E’s proposal was widely supported by the TSOs, although the work-in-progress version of the operational principles could not be approved. ENTSO-E continues its discussions with EMS and KOSTT.

The continental European TSOs support ENTSO-E in preventing further frequency deviations in the synchronised European power system (picture: photo composition using screenshots of Swissgrid’s frequency monitor and a press picture from Swissgrid)

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Frequency deviations occur again

10.07.2018

It was only this January that there were deviations from the 50Hz mid-frequency in the European transmission system which comprises the synchronised transmission grids of 25 countries. An obvious side effect of such a frequency decrease is a time loss of electric clocks steered by the system frequency. The deviations had their origin in the Serbia, Macedonia, Montenegro (SMM) control block, particular in the control areas of Kosovo and Serbia. The European transmission system operators (TSOs) immediately took necessary technical actions to limit the deviations and subsequently restore normal conditions.

Despite all the efforts by the European Union and the European Network of Transmission System Operators for Electricity (ENTSO-E) to reach a sustainable energy agreement between the competent authorities of Serbia and Kosovo, the controversy has not yet been resolved. As a consequence of this, ENTSO-E again has to report frequency deviations in the continental system that occurred on 6 July. Fortunately, the European TSOs have recently introduced a new compensation programme that will automatically start when the grid time deviation exceeds 60 seconds. Thanks to this programme, the time delay was kept below 60 seconds and the deviation has already been readjusted.

ENTSO-E continues to promote a political arrangement and welcomes the continued commitment of the European authorities to settle the dispute. Nevertheless, the continental European TSOs and ENTSO-E reserve the possibility of sanctions if the national TSOs involved do not appear willing to find a solution to the conflict, which is regional only in origin, but Europe-wide in terms of impact.

ENTSO-E yet again reports frequency deviations in the continental European power system deriving from the control areas of Kosovo and Serbia.

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> See ENTSO-E press release (html)
> See frequency monitor operated by Swiss TSO Swissgrid (html)

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Austrian research on battery based balancing

17.05.2018

The energy transition makes every market participant consider how to adapt to the rapidly changing conditions within the energy sector. Among other things, this means for the electric transmission system operators (TSOs) to respond to the weather dependence and thus volatility of the wind and solar energy generation. Dr. Ulrike Baumgartner-Gabitzer, CEO of the Austrian TSCNET shareholder APG, specifies the relating strategy of the TSO: “As APG we try to meet these challenges with the search for technological innovations.”

The modernisation and extension of the grid is undoubtedly of great importance, but TSOs need to think beyond that. Electricity grids increasingly require highly dynamic system elements that can compensate for short-term frequency deviations. In this context, storage technologies to stabilise the power grid are worthy of profound consideration. For this reason, together with the Austrian Institute of Technology, the Vienna Technical University and three subsidaries of Verbund, Austria‘s largest electricity provider, APG has launched a technology-neutral research project on battery-based balancing solutions: “Advanced Balancing Services for Transmission System Operators”, short ABS4TSOS.

The name similarity to the vehicle assistance system ABS (Anti-lock braking system) is by no means a coincidence. ABS4TSOS aims at automatic support systems and new mechanisms for the operation of the grid, which contribute to the maintenance of frequency stability and are therefore somewhat analogous to ABS. This includes all possible applications of a battery storage system in order to increase supply security. “ABS4TSO will address the question, in which way storage technologies can contribute to stabilising the grid in the future,” comments Dr. Baumgartner-Gabitzer.

In June 2019, the operation of the specifically designed battery storage system will commence at APG‘s substation Wien Südost. Subsequently, system functions and possibilities will be thoroughly examined. The project runs until the end of April 2021 and is endowed with €2.6m, which are borne by the project partners and the Austrian Climate and Energy Fund.

> See APG press release, in German (html)

Picture: APG

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Frequency deviations have ceased

09.03.2018

The European Network of Transmission System Operators for Electricity (ENTSO-E) and TSCNET shareholder Swissgrid, the Swiss transmission system operator (TSO), have reported minor but continuing deviations from the mean frequency value of 50Hz within the continental European power system. Swissgrid is responsible for monitoring the frequency in the pan-European network, which comprises the synchronised transmission grids of 25 countries. Deviations have been occurring continously since mid-January and have led to a slight decline in the average of the electrical frequency ‒ something that has never happened before in continental Europe. The missing energy amounts to 113GWh.

Although the supply security never has been at risk, a side effect of the frequency decrease was noticeable even to the ordinary citizen without specific technological knowledge. Since the average frequency of the time period concerned was only around 49.996Hz, it directly affected some electric clocks steered by the system frequency instead of a quartz crystal (e.g. oven clocks or clocks for programming the heating system). These clocks could have been almost six minutes slow.

ENTSO-E, in close cooperation with the TSOs, has considered all possible technical options to solve the problem and by now, the frequency deviations frequency in continental Europe have ceased. A second step is returning the missing energy to the system and restoring the normal situation. In addition, ENTSO-E calls on the European governments to take action swiftly: Since the issue also has a political dimension, politics must keep pace with technology. In this specific case, the deviations originally emanated from the Serbia, Macedonia, Montenegro (SMM) control block, particular from the control areas of Kosovo and Serbia. It goes without saying, that all technological approaches are limited and a deviation risk still remains, if no political solution is reached.

> See Swissgrid news release (html)
> See ENTSO-E press release (html)
> See frequency monitor operated by Swiss TSO Swissgrid (html)

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