Analysis of the two systems splits and one inter-area oscillation within the Continental European Synchronous Area in year 2021


Date: Wednesday, May 25                              Time: 10:30 am – 12:00 pm (CEST)


Name of the organizer: Asja Derviskadic

Organization: Swissgrid, Switzerland

Email: asja.derviskadic@swissgrid.ch

Short biography of the chair: Asja Derviškadić received the B.Sc. and M.Sc. degrees (Hons.) in electrical engineering from the University of Rome “La Sapienza,” Rome, Italy, in 2012 and 2015, respectively, and the Ph.D. degree in electrical engineering from the Swiss Federal Institute of Technology of Lausanne (EPFL), Lausanne, Switzerland, in 2019. In 2019-2020 she was a Postdoctoral researcher at the Distributed Electrical Systems Laboratory (DESL) of EPFL and her research interests focused on synchronized sensing technologies for wide-area situational awareness of electrical grids operating in non-stationary conditions. She is currently with the short-term network modeling team of Swissgrid, the Swiss transmission system operator, where she works as grid studies engineer. She is a member of the ENTSO-E SubGroup System Protection and Dynamics.

Panel Abstract: During year 2021, the Continental European (CE) Synchronous Area faced several incidents that seriously challenged its interconnected nature. Thanks to the close collaboration of European TSOs through the ENTSO-E, and thanks to the inherent resilience of such a large power system, none of these events lead to catastrophic consequences and the system was brought back into a safe operating mode after few hours. First, on January 8th due to a large power flow from South-East to North-West Europe, cascaded trips of several transmission elements split the system into two separate regions, with the separation line crossing Croatia, Serbia, and Romania. Then, on July 24th the Iberic Peninsula was separated form the rest of the CE power system due to a wildfire in the eastern French double circuit near the Spain-France interconnection that triggered the automatic protection devices of the tie-lines and led to further cascaded trips. Finally, on October 11th a long-lasting undamped oscillation excited the East-West mode. The ENTSO-E SubGroup System Protection and Dynamics had a leading role in carrying out the technical investigations that followed these events and actively contributed to the definition of future recommendations. The tutorial/panel expands on the methods and tools that were used during such investigations, with a particular focus on dynamic stability criteria.


Panelist 1:

Name: Asja Derviskadic

Organization: Swissgrid, Switzerland

Email: asja.derviskadic@swissgrid.ch

Short bio and photo: included above in the Panel Chair section

Title of presentation: Analysis of the two systems splits and one inter-area oscillation within the Continental European Synchronous Area in year 2021

Abstract: During year 2021, the Continental European (CE) Synchronous Area faced several incidents that seriously challenged its interconnected nature. Thanks to the close collaboration of European TSOs through the ENTSO-E, and thanks to the inherent resilience of such a large power system, none of these events lead to catastrophic consequences and the system was brought back into a safe operating mode after few hours. First, on January 8th due to a large power flow from South-East to North-West Europe, cascaded trips of several transmission elements split the system into two separate regions, with the separation line crossing Croatia, Serbia, and Romania. Then, on July 24th the Iberian Peninsula was separated from the rest of the CE power system due to a wildfire in the eastern French double circuit near the Spain-France interconnection that triggered the automatic protection devices of the tie-lines and led to further cascaded trips. Finally, on October 11th a long-lasting undamped oscillation excited the East-West mode. The ENTSO-E SubGroup System Protection and Dynamics had a leading role in carrying out the technical investigations that followed these events and actively contributed to the definition of future recommendations. The tutorial/panel expands on the methods and tools that were used during such investigations, with a particular focus on dynamic stability criteria.


Panelist 2:

Name: Agustín Díaz García

Organization:  REE, Spain

Email: agustindiaz@gmail.com

Short biography: Agustín Díaz García is Industrial Engineer (Electricity) of Universidad Politécnica de Madrid (Spain). During his years at university he made collaborations with Physics and Automatics departments. He began his career working as electrical consultant for Network Studies and Wind Power departments at Iberdrola Engineering. On 2007 he entered Network Studies Department in Red Electrica de España (Spanish TSO) as senior engineer. Since that, his work has been focused on system stability, renewable power impact in the electricity system, requirements for generators, network studies for conventional generator access to the network, power quality, etc. Nowadays Agustin is co-convenor of the System Protection and Dynamics group of Continental Europe at ENTSO-E.

Title of presentation: Power system separation of the Iberian Peninsula from Continental Europe on 24 July 2021

Abstract: On 24 July 2021 at 16:36 CET, due to a major incident in France, the transmission systems of Portugal and Spain, together with a small part of the French transmission system, were disconnected from the synchronous area Continental Europe for just over 30 minutes. During the disturbance, the frequency deviation of the large part of the Continental Europe was kept within a safety margin, whereas in the Iberian Peninsula the deviation was more substantial and involved further emergency measures according to the predefined plans. The panel presents the results of the incident investigations, providing a comprehensive analytical overview of the incident – the causes and the consequences – and proposing recommendations to prevent and mitigate the consequences of similar events in the future.


Panelist 3:

Name: Walter Sattinger

Organization: Swissgrid, Switzerland

Email: walter.sattinger@swissgrid.ch

Short biography: Walter Sattinger has extensive experience in power system dynamic analysis. He has been working for 34 years in the field of power system modelling and power system control. In several studies he has worked in all required project stages from the on-site data collection to the organisation and execution of system tests, dynamic model identification, system modelling, performing of studies, reports and finally the presentation of the study results. Currently he is working as a project engineer at the interface between planning and operation and he is responsible for the implementation of concepts to enhance system security. He is currently co-convenor of the System Protection and Dynamics group of Continental Europe at ENTSO-E and CIGRE convenor for C2.18 WG. He has received his PhD in 1995 and degree of electrical engineer in 1988 from the Univ. of Stuttgart, Germany.

Title of presentation: Analysis of the Continental European inter-area oscillations on 11 October 2021

Abstract: On 11 October 2021 at 9, an unexpected opening of a tie-line interconnecting the French and the Spanish grids, triggered an oscillatory incident in Continental Europe electricity system. The East-Center-West mode was excited, characterized by undamped oscillations at 0.18 Hz. The oscillation was mitigated by changing the control mode of the interconnecting DC HVDC links. The panel presents the results of the event analysis, identifies the causes of the incident, describes the countermeasures taken to stop the oscillation and proposes recommendations on how to avoid long-lasting undamped oscillations.


Panelist 4:

Name: Giorgio Giannuzzi

Organization: Terna, Italy

Email: giorgio.giannuzzi@terna.it

Short biography: Giorgio Giannuzzi (1967) received his Electric Engineering degree from the University of Rome. Until December 2000 he worked for ABB, where he was in charge of network studies, protection and control applications, with special reference to RTU apparatus and data engineering issues. Since 2001 he serves TERNA as expert in defense plans/systems, dynamic studies, protection, telecontrol and substation automation. Between years 2004 and 2011 he coordinated the study, design and activation of Wide Area Defence system (including Interruptible Customers System) and Wide Area Monitoring System. Until 2009 he was a member of a UCTE Expert Group on Power System Stability. In 2010 he joined ENTSO-E System Protection and Dynamics Group and starting from 2014 is the co-Convenor, coordinating the European evaluation over Dispersed Generation impact on system security, Defense Systems and Power System dynamics studies for ENTSO-E. Currently is responsible of the Engineering Department of National Dispatching Centre.

Title of presentation: Separation of the Continental Europe power system on 8 January 2021

Abstract: On 8 January 2021 at 14:05 CET the synchronous area of Continental Europe was separated into two parts due to outages of several transmission network elements in a very short time, with the separation line crossing Croatia, Serbia, and Romania. The system separation resulted in a deficit of power (approx. -6.3 GW) in the North-West Area and a surplus of power (approx. +6.3 GW) in the South-East Area, resulting in turn in a frequency decrease in the North-West Area and a frequency increase in the South-East Area. The panel presents the results of the investigations after the incident, provides a comprehensive analytical overview of the incident, including its causes and its consequences, and proposes recommendations to prevent and mitigate the consequences of similar events in the future.