System Operations Reports
Pan-European Technical Studies
- Use of Travelling Waves Principle in Protection Systems and Related Automations
- HVDC Links in System Operations - Technical paper
- Operational Limits and Conditions for Mutual Frequency support over HVDC
- Bus Bar Differential Protection Report
- Short Circuit Contribution of Power Electronics Connecting Generators and Protection report
- Best protection practices for HV EHV AC transmission system
- Operational Limits and Conditions for Frequency Coupling
- System protection behavior and settings during system disturbances
- High Penetration of Power Electronic Interfaced Power Sources and the Potential Contribution of Grid Forming Converters
Continental Europe Technical Studies
- System Defence Plan – 2022 report
- Inertia and Rate of Change of Frequency – 2020 report
- Oscillation Event on 3 December 2017
- Analysis of ce inter-area oscillations 1st December 2016
- SPD DSA Task Force - Dynamic Security Assessment (DSA)
- Determining generator fault clearing time for the synchronous zone of Continental Europe
- Overfrequency Control Schemes – Recommendations for the Synchronous Area of Continental Europe
- System Dynamic Issues for the synchronous zone of Continental Europe
- Frequency Stability Evaluation Criteria for the Synchronous Zone of Continental Europe – Inertia Report
- Final report on the Blackout in Türkiye 31st March 2015 (V1.0)
- 2015 Wide Area Monitoring Report (V5)
- 2015 Dynamic Line Rating for Overhead Lines
Further Reports and Studies
- Quality of Datasets and Calculations (March 2015)
- Dispersed Generation Impact on Continental Europe Region Security (November 2014)
- Controller Test Report (November 2013)
- Automatic Frequency Disconnection Settings of Installed Photovoltaic (PV) Panels in Some European Countries (May 2012)
- Special Protection Schemes (April 2012)
- Best Protection Practices for HV and EHV Transmission Systems of ENTSO-E CE Area Electrical Grids (April 2012)
- Analysis of CE Inter-Area Oscillations of 19 and 24 February 2011 (September 2011)
- Technical Background and Recommendations for Defence Plans in the Continental Europe Synchronous area (October 2010)
ENTSO-E Dynamic Model of Continental Europe
The model describes the general dynamic behaviour of the ENTSO-E Continental Europe power system and is suitable for transient analysis. The model is able to represent the main frequency response of the system as well as the main inter-area oscillation modes.
In order to simplify the model and be able to make the network data available to third parties, a few simplifications and anonymisation steps were performed. However, all these adjustments were done in such a way that the dynamic behaviour of the power system is not affected. More details can be found in the Initial Dynamic Model Instruction manual.
The model is currently available in PowerFactory, Netomac, Eurostag, and PSS/E proprietary formats.
At PowerTech Eindhoven 2015 conference (Towards Future Power Systems and Emerging Technologies), the paper [Paper] Dynamic Study Model for the Interconnected Power System of Continental Europe in Different Simulation Tools was presented.
The use of this model is recommended exclusively under the supervision of ENTSO-E dynamic experts. 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.
Please note that the model cannot be delivered to private persons. A legal entity has to sign the Request Form and take over the responsibilities stemming from it.
Please send the completed and signed Request Form to: firstname.lastname@example.org.
The validity of the Request Form will be checked. Please expect that ENTSO-E dynamic experts will contact you to discuss the usability of the model for your project. It is expected that the model will be used for research. It will be delivered by email containing a link for downloading the requested proprietary format of the model.
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.
External documents mentioned in SAFA Policies
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.
Over the course of 2022, Ukrenergo and Moldelectrica will continue with the implementation of the Catalogue of Measures in preparation for the beginning of the trial synchronous operation, that is currently planned in 2023. Ukrenergo and Moldelectrica will also perform two isolated operation tests in 2022, planned for the summer and the winter, to demonstrate their ability to operate their power system in a secure manner with the appropriate reaction of load-frequency control, according to the standards of Continental Europe Transmission System Operators (TSOs).
A more precise timeframe for the start of the trial synchronous operation and the associated technical conditions (including details on the allowed commercial import/export capacity) will be communicated when the Continental Europe TSOs have assessed the results of the two isolated operation tests and the progress of the implementation of the Catalogue of Measures. This assessment is expected to take place in late 2022.
For further information, please contact ENTSO-E Communications by email: email@example.com.
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
- Main Agreement
- Annex Load-Frequency Control & Reserves
- Annex Electricity Balancing
- Annex Operational Planning
- Annex Operational Security
- Annex Emergency and Restoration
- Annex Capacity Calculation and Congestion Management
- Annex Forward Capacity Allocation
Nordic Technical Studies
Guidelines for the classification of grid disturbances above 100 kV have been replaced with ENTSO-E Disturbance Definitions for the Power system above 100 kV
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 parallel projects within the domain of automatic frequency control with frequency quality and stability as the main objective.
The project portfolio has consisted of evaluating the performance of and requirements on
- Frequency containment process (FCP)
- System inertia
- Frequency quality
- Under frequency load shedding (UFLS)
The goals, results and next steps for each of the individual projects are presented in a high level executive summary.
The individual project reports can be downloaded here:
- Reports on Frequency containment process
- Reports on System inertia
- Reports on Frequency quality
- Report on Under Frequency Load Shedding
Reports on future system inertia
- 2021 ENTSO-E HVDC Utilisation and Unavailability Statistics
- Nordic and Baltic Grid Disturbance Statistics 2020
- ENTSO-E HVDC Utilisation and Unavailability Statistics 2020
- Nordic and Baltic Grid Disturbance Statistics 2019
- Nordic and Baltic HVDC Utilisation and Unavailability Statistics 2019
- Nordic and Baltic Grid Disturbance Statistics 2018
- Nordic and Baltic HVAC Disturbance Statistics 2018
- Nordic HVDC Utilisation and Unavailability Statistics 2018
- Nordic and Baltic HVAC Disturbance Statistics 2017
- Nordic and Baltic HVDC Disturbance Statistics 2017
- Nordic and Baltic HVAC Disturbance Statistics 2016
- Nordic and Baltic HVDC Utilization and Unavailability Statistics 2016
- Nordic and Baltic HVAC Disturbance Statistics 2015
- Nordic and Baltic HVDC Utilization and Unavailability Statistics 2015
- Nordic and Baltic HVAC Disturbance Statistics 2014
- Nordic and Baltic HVDC Utilization and Unavailability Statistics 2014
- Nordic HVAC Grid Disturbance Statistics 2013
- Nordic HVDC Utilization and Unavailability Statistics 2013
- Nordic Disturbance Statistics 2012
- Nordic Disturbance Statistics 2011
- Nordic Disturbance Statistics 2010
- Nordic Disturbance Statistics 2009
- Nordic Disturbance Statistics from 1999 to 2008 (Nordel)
- Nordic System Operation Workshop 1.12.2016
- Nordic System Operations Workshop 10.12.2014
- Nordic Automatic FRR Workshop 9.5.2012
- Nordic System Operations Workshop 28.9.2011
- Nordic System Operations Workshop 13.4.2010
- Nordic summary of the winter 2010-2011
- Nordic winter power balance 2010-2011
- Evaluation of the ramping restriction in the energy market (PDF, 379KB)
- ENTSO-E’s views on the offshore grid development in the North Seas (PDF, 1.42MB)
- Impact of increased amounts of renewable energy on Nordic power system operation
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.
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.
January 2019 CE Significant Frequency Deviations
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
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.
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.
- 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.
- Commission Regulation (EU) 2017/1485 of 2 August 2017 establishing a guideline on electricity transmission system operation (System Operation Guideline, SO GL)
- ENTSO-E publications:
- 8 January 2021: System split registered in the synchronous area of Continental Europe – Incident now resolved
- 15 January 2021: System Separation in the Continental Europe Synchronous Area on 8 January 2021 – update
- 26 January 2021: System separation in the Continental Europe Synchronous Area on 8 January 2021 – 2nd update
- ACER news:
- ACER, firstname.lastname@example.org, T: + 32 (0) 484 66 85 99
- ENTSO-E, email@example.com, T: +32 (0) 476 97 50 93.
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
- 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.
- 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.
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.
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.
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.
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.
If the report you are looking for is not contained in the page above, you should try the system operations reports archive.