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System Operations Reports

Pan-European Technical Studies

ENTSO-E’s Common Grid Model

Continental Europe Technical Studies

Dispersed Generation Impact on Continental Europe Region Security – 2014 report

Dispersed Generation Impact on Continental Europe Region Security – 2013 report

Further Reports and Studies

ENTSO-E Dynamic Model of Continental Europe

The model includes a detailed description of 400/230 kV transmission systems of all Continental Europe countries, with no details on the sub-transmission and distribution networks. For this reason, the model describes the general dynamic behaviour of the Continental European power system. The model is suitable for performing frequency stability analysis and small signal stability by representing the main frequency response of the system as well as the main inter-area oscillation modes. The model might also be used as a boundary network for detailed stability studies if the area of interest is replaced by a detailed dynamic model of that specific region. The Continental European dynamic model itself is not meant to be used for other stability studies, such as voltage stability, transient stability, or even harmonics. Also, the model is not suitable to study other local phenomena such as system protection of lines, special protection schemes, congestions of lines and other specific control schemes.

In order to simplify the model and being able to make the network data available to third parties, a few further simplifications and anonymisation steps were performed, while still keeping its dynamic behaviour unchanged. More details about model construction and validation can be found in the Dynamic model of Continental Europe V2 Instruction manual.

The model is currently available in DigSilent PowerFactory and PSS/E proprietary formats.

The use of this model is recommended exclusively under the supervision of ENTSO-E dynamic experts. It is expected that the model will be used for research purposes and for specific activities which must be clearly described.

A party wishing to access the Initial Dynamic Models provided by ENTSO-E will be required to sign a Request Form that includes non-disclosure provisions. If you are a University use The Request Form for Universities. The Request Form must be sent to idm@entsoe.eu.

Please note that the model cannot be delivered to private persons: A legal entity must sign the Request Form and take over the responsibilities stemming from it. Persons signing the request on behalf of the Recipient, personally represent and warrant that they are duly authorized to do so. ENTSO-E may request the signing persons provide proof of their authorization to act on behalf of the Recipient.

The validity of the Request Form will be checked. ENTSO-E dynamic experts might contact you to discuss the usability of the model for your project. The model will be delivered through a link for downloading it in the requested proprietary format.

Continental Europe Synchronous Area Framework Agreement

Since its entry into force the 14 April 2019, The Synchronous Area Framework (SAFA) for the ENTSO-E Regional Group Continental Europe replaces and supersedes the 2005 Multilateral Agreement Operation Handbook. It develops the Synchronous Area Operation Agreement according to Article 118 of the System Operations Guidelines, one of the eight European network codes and guidelines, and the SAFA includes also necessary agreements among the TSOs of Continental Europe not bound by EU law.

SAFA documents

TitleVersion
Policy on Load-Frequency Control and Reserves241126
Policy on Scheduling220215
Policy on Accounting and Settlement240423
Policy on Coordinated Operational Planning230620
Policy on Emergency and Restoration231120
Policy on Data Exchange220215
List of Definitions220215
List of Parties240101

External documents mentioned in SAFA Policies

TitleVersion
Policy on LFCR - A1 - SOGL_A153.2_FCR dimensioning190414
Policy on LFCR - A2 - SOGL_A154.2_Additional properties of FCR210928
Policy on LFCR - A5 - SOGL_A176.1_A177.1_Limits FRR exchange and sharing between SA190414
Policy on LFCR - A6 - SOGL_A178.1_A179.1_Limits RR exchange and sharing between SA190414
Policy on LFCR - A7 - SOGL_A141.2_CE LFC blocks determination220720
Policy on AS - A1 - EBGL_A50.3_FSkar_methodology_CCFR200407
Policy on AS - A2 - EBGL_A51.1_FSkar_methodology_CCU200407
Policy on AS - C13 Appendix 1_The beneficiary owner’s statement211130
Policy on AS - C13 Appendix 2_The verification questionnaire211130
Policy on COP - A1 - SOGL_67.1_70.1_CGM methodology190414
Policy on COP - A2 - SOGL_75_CSA methodology190414
Policy on COP - A3 - SOGL_84_RAOC methodology190414
Policy on COP - C1 - Target OPC Process Implementation document190414
Policy on DE - SOGL_40.6_ KORRR190414

Baltic synchronisation with CE

On 27 May 2019, TSOs of Regional Group Continental Europe (RG CE) and the Baltic TSOs signed the “Agreement on the Conditions of the Future Synchronous Interconnection of Power System of Baltic States and Power System of Continental Europe”. The Agreement specifies the technical requirements to comply with to enable secure interconnection of the Baltic States with the CE synchronous area.

The requirements are related to system operation of Baltic TSOs, which must be in line with the so called Operational Framework. The synchronization is planned for 2025.

Future interconnection of Ukraine and Moldova with the Continental Europe Power System

On 28 June 2017, TSOs of Continental Europe signed with Ukrenergo and Moldelectrica the “Agreements on the Conditions of the Future Interconnection of the Power System of Ukraine and Moldova with the Power System of Continental Europe”.

The Agreements specify that, before any interconnection can be achieved, Ukrenergo and Moldelectrica must implement a Catalogue of Measures including a series of technical requirements that will ensure a secure interconnection of Ukraine and Moldova with the synchronous area. The Catalogue of Measures is in line with the Continental Europe Synchronous Area Framework Agreement (SAFA).

In addition, the Agreements provide for studies to be carried out in order to verify whether additional measures are necessary to allow for a synchronous connection of Ukraine and Moldova with the Continental Europe power system. These studies were finalized at the end of 2021 and have shown that additional measures are required to ensure the stability of the interconnected power system. These measures will be added to the Catalogues of Measures included in the Agreements.

Following an urgent request by Ukrenergo and Moldova for emergency synchronisation, the TSOs of Continental Europe agreed to start on 16 March 2022 the trial synchronisation of the Continental European Power System with the power systems of Ukraine and Moldova.

On 28 November 2023, the Continental Europe TSOs confirmed the completion of the synchronisation project for Ukrenergo, following their sufficient compliance with all measures included in their Catalogue of Measures.

Over the course of 2024 and 2025, Moldelectrica will continue with the implementation of the Catalogue of Measures in order to finalize their permanent synchronization, that is currently planned in 2025.

For further information, please contact ENTSO-E Communications by email: media@entsoe.eu.

ENTSO-E Grid Disturbance Definitions for the Power System above 100 kV

ENTSO-E Grid Disturbance Definitions for the Power System above 100 kV describes a common set of principles for identifying and defining incidents, disturbances and faults in the power grid. It is based on existing standards (i.e. IEEE and IEC) and existing EU TSOs’ processes.

This document is an update to 2018 version, which was used as a guideline for collecting information for the annually published Nordic and Baltic Grid Disturbance Statistics report. The updated 2021 version is intended to form the basis of common grid disturbance statistics for all European countries, as it establishes common practices for registering and reporting this information. The aim is to reduce potential double registering of data, increase and level the quality of the data and make it easier to exchange and derive data for new use in the future.

Nordic System Operation Agreement (Nordic SOA)

The below reports and publications concern ENTSO-E’s Nordic region.

The new Nordic system operation agreement (Nordic SOA) entered into force on 14th August 2019. The new Nordic SOA supersedes and replaces the previous SOA.

Nordic System Operation Agreement

Nordic Technical Studies

Balancing

Guidelines

Mid-term adequacy forecast

Frequency stability in the Nordic system

The Nordic Transmission System Operators (Energinet, Fingrid, Statnett and Svenska kraftnät) have through the Nordic Analysis Group (NAG) carried out several projects within the domain of automatic frequency control with frequency quality and stability as the main objective. The group is continuously conduction analysis within this domain. 

NAG is evaluating the performance of and requirements on

  1. Frequency containment process (FCP)
  2. System inertia (incl. FFR)
  3. Frequency quality and risk levels
  4. Low frequency demand disconnection (LFDD)

An executive summary of the group’s 5 year plan can be found here: 

Previous reports can be found here:

Reports on Frequency containment process

Reports on System inertia

Reports on Frequency quality

Report on Under Frequency Load Shedding

System design report

Minimum inertia study**

Fault Statistics

Workshop Material

Reports

2022-2023

2021-2022

2020-2021

2019-2020

2018-2019

2017-2018

2016-2017

2015-2016

2014-2015

2013-2014

2012-2013

2011-2012

2010-2011

2009-2010

Technical cooperation with third-country TSOs

This document provides recommendations for the cooperation of ENTSO-E with third-country TSOs and is adopted in accordance with Article 8(3)(c) Regulation (EC) No 714 / 2009.

In this document, the role of ENTSO-E is to facilitate the cooperation and coordination between TSOs to ensure effective and transparent access to the transmission networks and to provide coordinated and forward-looking planning. Supporting the technical evolution of the transmission system, including the creation of interconnection capacities with third-party TSOs, is a fundamental aspect of ENTSO-E’s remit.

Sharing best practices on traditional and new issues will help all involved parties on their way towards a sustainable energy future.

In maintaining and continuously improving these recommendations, ENTSO-E will continue to review and update these recommendations, taking into account practical experience of their implementation. In addition, ENTSO-E intends in the future to consult with third-country TSOs with the intention of making changes that would be beneficial to this framework for technical cooperation.

Recommendations relating to the coordination of technical cooperation between Union and third-country TSOs – 2016 report

January 2017 critical grid situation

The report looks at the consequences on systems and markets in the most impacted countries. If the report shows good cooperation notably through Regional Service Coordinators in Western Europe, the cooperation in South East Europe seems to have suffered from a lack of policy and regulatory alignment.

The report lists a series of recommendations like the enhancement of the methodology used in Outlooks to cover more adequacy risks. Today the methodology is not able to forecast situations like the South East Europe January 2017 cold spell. ENTSO-E is committed to make these improvements in time for the next winter outlook.

On net generating capacity, the decrease of fossil fuel (except gas) and the increase in wind and solar is confirmed compared to last summer.

Read Managing critical grid situations - Success and Challenges

Annex - A market analysis of the January 2017 cold spell in Europe

View original news release →

January 2019 CE Significant Frequency Deviations

Read the report

Deterministic Frequency Deviations Report

Read the Deterministic Frequency Deviations Report

Long Lasting Frequency Deviations

The Long Lasting Frequency Deviations Measures taken by Continental European TSOs to address Long Lasting Frequency Deviations

Read the Measures on the Long Lasting Frequency Deviations

January 2021 CE system separation

ENTSO-E publishes the Interim Report on the Continental Europe Synchronous Area Separation that took place on 8 January 2021.

This Interim Report follows the initial information published on 8 January 2021 and two updates of 15 and 26 January 2021. The Report recounts the evolution of system conditions during the event, the steps taken during the resynchronisation and shows the communication between the coordination centres/synchronous area monitors and the TSOs. It also includes the assessment of the incident based on the Incident Classification Scale (ICS) Methodology (developed in accordance with Regulation (EU) 2019/943), according to which the incident is classified as a scale 2.

This Interim Report is the result of an intensive process to collect and prepare data on the event, started immediately after its resolution. It is to serve as basis for further investigation by an Expert Panel which according to the ICS Methodology for scale 2 incidents, shall prepare a Final Report.

Read the Interim Report.

ACER and ENTSO-E investigate the 8 January electricity system separation

  • ACER and national regulators join ENTSO-E’s Expert Panel investigating the electricity system separation of the Continental Europe synchronous area on 8 January 2021
  • The Expert Panel will identify the causes and make recommendations in a Final Report Europe’s electricity system split in two separate regions on 8th January 2021 resulting in transmission system outages.

Expert Panel begins its investigation

Based on preliminary data of Transmission System Operators (TSOs), the system separation of the Continental Europe synchronous area, which lasted just over an hour, is classified as a scale 2 (or “extensive”) incident as per ENTSO-E’s Incident Classification Scale (ICS)1.

According to the ICS Methodology, for scale 2 incidents, a final report shall be prepared by an Expert Panel, where relevant National Regulatory Authorities (NRAs) and the European Agency for the Cooperation of Energy Regulators (ACER) may be involved upon their request. ENTSO-E has created the Expert Panel, inviting ACER and NRAs to join it. The Expert Panel will first meet on 4 March.

ENTSO-E’s Interim Report published

An intensive process started immediately after the event has been resolved, in order to collect and prepare factual data. The Interim Report published today by ENTSO-E contains the data gathered, initial findings on the sequences of events and timeframes. The Interim Report is the basis for the formal investigation by an Expert Panel.

Expert Panel’s Final Report has 22 recommendations

The Final Report describes the sequence of events and violations of operational security limits. It explains the causes and has recommendations to prevent such incidents in the future. ACER and ENTSO-E are committed to fulfilling their legal obligations specified in the System Operations Guideline and ICS Methodology.

Related Links:

Notes

  1. Incidents Classification Scale. The ICS Methodology has been developed in accordance with Regulation (EU) 2019/943 of the European Parliament and of the Council of 5 June 2019. It has been updated 2019, to fulfil the objectives of Article 15 of SO GL quoted above.
  2. Commission Regulation (EU) 2017/1485 of 2 August 2017 establishing a guideline on electricity transmission system operation (System Operation Guideline, SO GL)
  3. ENTSO-E publications:
  4. ACER news:

Press contacts:

Final Report on the local power grid incident in Rogowiec (Poland) substation on 17 May 2021

The Expert Panel composed of ENTSO-E, Polskie Sieci Elektroenergetyczne S.A. (PSE, the Polish Transmission System Operator (TSO)), ACER and relevant National Regulatory Authority (NRA) representatives publish their Final Report on the Local Grid Incident in Rogowiec (Poland) substation that occurred on 17 May 2021, issued in accordance with the System Operation Guideline (SO GL) and the Incident Classification Scale (ICS) Methodology. The report is now available.

The incident – classified as a scale 2 incident according to the ICS Methodology – led to the tripping of ten generation units of the Bełchatów power plant and to a loss of 3,322 MW of generation capacity. The cause of the incident was a human error. Incorrect manipulation of the line earthing switch led to a short circuit in the 400 kV Rogowiec switchyard.

Thanks to the swift remedial actions taken by PSE, as well as the emergency support from neighbouring TSOs and cooperation with the coordination centre, the power system was operating within the security limits approximately 20 minutes. The market continued to function according to the standard procedures in all timeframes. No consumer was disconnected and there was no negative impact on the operation of the synchronously interconnected power system of Continental Europe. Following the investigation, the Expert Panel presents today its report which includes a few recommendations.

Recommendations of Expert Panel

  1. In substations where a large-scale incident can lead to more than 3000 MW of generation lost, the TSO shall:
    • Possess a document showing the compliance of the grounding circuits to technical requirements coming from the tests done during the commissioning of the substation, or
    • Possess a document showing the compliance of the grounding circuits to technical requirements coming from the tests done after any substantial modifications of the grounding circuits, or
    • Measure and check the compliance of the grounding circuits to technical requirements in case documents mentioned in paragraphs a. and b. are not available.
  2. In order to guarantee a better resilience, in the relevant substations and double lines of the network which can cause at least scale 2 incident according to ICS methodology, have a dedicated reinforced maintenance of these structures.

Notes

Incident Classification Scale. The ICS Methodology has been developed in accordance with Regulation (EU) 2019/943 of the European Parliament and of the Council of 5 June 2019. It was updated in 2019, to fulfil the objectives of Article 15 of SO GL quoted above.

Commission Regulation (EU) 2017/1485 of 2 August 2017 establishing a guideline on electricity transmission system operation (System Operation Guideline, SO GL).

Separation of the Continental Europe Synchronous Area on 24 July 2021

On 12 November 2021, ENTSO-E published the Factual Report on the Continental Europe Synchronous Area Separation that took place on 24 July 2021.

This Factual Report follows the initial information published on 24 July 2021 and two updates of 20 August and 22 October 2021. The Report recounts the evolution of system conditions during the event, the steps taken during the resynchronisation and shows the communication between the TSOs. It also includes the assessment of the incident based on the Incident Classification Scale (ICS) Methodology (developed in accordance with Regulation (EU) 2019/943), according to which the incident is classified as a scale 2.

This Factual Report is the result of an intensive process to collect and prepare data on the event, started immediately after its resolution. It is to serve as basis for further investigation by an Expert Panel which according to the ICS Methodology for scale 2 incidents, shall prepare a Final Report.

Read the Factual Report.

Final report on the power system separation of Iberia from Continental Europe on 24 July 2021

No major damage to the power system but some customers were disconnected

Avoiding tripping of generation connected to distribution systems is essential to maintaining system security

The Expert Panel composed of ENTSO-E and the relevant Transmission System Operators (TSOs) as well as ACER and relevant National Regulatory Authority (NRA) representatives publish their Final Report on an incident which separated on 24 July 2021 for about an hour the Iberian Peninsula from the rest of the Continental Europe power system.

In view of the customer disconnections, the incident was ranked level two according to the ICS Methodology and an expert panel was set up on 22 October 2021 to carry out an investigation.

After several months of intensive and close collaboration of all parties involved, the expert panel issued its final report. It provides a comprehensive analytical overview of the incident – the causes and the consequences - and proposes recommendations to prevent and mitigate the consequences of similar events in the future.

The Expert Panel’s analysis concludes that this incident was atypical in that it resulted from the failure of an efficient and suitable communication channel between the emergency services and the TSO. It did not originate from any faults in system operation or planning. The system defence plans functioned properly and coordinated measures were activated quickly.

Avoiding tripping of generation connected to distribution systems is essential to maintaining system security

The incident revealed that the limits of stable system operation can be reached, even if all security evaluations are executed correctly and timely. With the increase in distributed generation connected to the grid to achieve the de-carbonisation of the energy system, non-compliance with the technical requirements of the binding EU network codes may generate uncontrollable and unmanageable breaches of the security of the electricity system.

Key Recommendations

The expert panel makes several recommendations and in particular,

  • One Key Recommendation is that NRAs, TSOs, Distribution System Operators (DSOs) and Owners of Distributed Generation Units work together to ensure that the mandatory system security requirements are implemented and monitored for their compliance. The Expert Panel recommends that this issue is addressed at the European level;
  • A second Key Recommendation is for TSOs to continuously develop and improve their environmental risk identification and mitigation processes to be prepared for a potential increase in their occurrence due to the effects of climate change.

The Expert Panel calls for ENTSO-E/TSOs and ACER/national regulators to follow up on the implementation of these recommendations to prevent and mitigate the consequences of similar incidents in the future.

Related links:

Grid Incident in South-East Europe on
21 June 2024

On Friday, 21 June 2024, a significant incident occurred in South-East Europe (SEE), which led to a major disruption in the power system of Continental Europe (CE). The incident resulted in a substantial loss of the capacity of supplying power with the consequence of disruption to meet temporally the electricity demand. This incident affected Albania (OST), Bosnia and Herzegovina (NOSBiH), Montenegro (CGES), and Croatia (HOPS). The event was characterised by a series of single episodes occurring in the transmission network, which led in the transmission network, which ultimately led to a (partial) blackout in these four countries.

ENTSO-E publishes the Interim (Factual) Report which provides a description of the system conditions before the incident, recounts the evolution those conditions during the event, as well as the steps taken directly after the incident took place. Furthermore, it outlines the communication between the coordination centres/synchronous area monitors and the TSOs. It also includes the assessment of the incident based on the Incident Classification Scale (ICS) Methodology (developed in accordance with Regulation (EU) 2019/943), according to which the incident is classified as a scale 3.

This Interim (Factual) Report is the result of an intensive process to collect and prepare data about the event which started immediately after its resolution. This report is to serve as basis for further investigation by an Expert Panel (composed of ENTSO-E, ACER and National Regulatory Authorities) shall prepare a Final Report.

Read the Interim Report

The Final Report on the Grid incident in South-East Europe

The final report on the grid incident of 21 June 2024 in the Western Balkan-Region highlights the value of international cooperation by the TSOs and RCCs It presents the gathered facts and the analysis of the causes of the incident in the Balkan region. The report also includes recommendations to improve system security in the future.
On Friday, 21 June 2024, a significant incident occurred in South-East Europe (SEE), leading to a major disruption in the Continental Europe (CE) power system. The incident resulted in a substantial loss of load and generation, affecting multiple countries including Albania (OST), Bosnia and Herzegovina (NOSBiH), Montenegro (CGES), and Croatia (HOPS). The event was characterised by series of outages occurring in the transmission network, which ultimately led to a (partial) blackout in these four countries. Normal operations were restored by the TSOs in the region immediately after the incident.
The final report identifies the following root causes of the incident:

  • The two initial short circuits were caused by vegetation that had grown too close to the power lines
  • The resulting outages on the grid affected more than one TSO, without the operators concerned having an overall view of the grid in the region.
  • When the voltage in the system decreased, the available measures were not sufficient to avoid a voltage collapse which ultimately led to the partial black-out in the region.

An Expert Panel was set up on 15 July 2024 to carry out an investigation. The Expert Panel composed of ENTSO-E and the relevant Transmission System Operators (TSOs) as well as ACER, relevant National Regulatory Authority (NRA) representatives and the RCC Investigation Subgroup. Their findings include recommendations for the TSOs which are detailed in the report. They include:

  • Ensuring adequate vegetation trimming is crucial for preventing short circuits and maintaining a secure and reliable power network. The report recommends a check on procedure for vegetation growth control.

  • The TSOs should extend their observability area in the neighbouring grids so they are informed on technical data in real time and have a more complete view of the grid in their region. This will allow them to assess the consequences of possible overload situations affecting powerlines in neighbouring grids that might impact their real-time operations.

TSOs should develop and implement shared standards in the light of these findings and reassess the procedures for handling voltage stability and overloads on powerlines.

Read the Final Report


Archive

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Archived Reports

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