The European Network of Transmission System Operators for Electricity (ENTSO-e) has published the final report of the Expert Panel on February 25. regarding the incident that occurred on June 21. 2024. This incident left a significant part of the consumers in Albania, Montenegro, Bosnia and Herzegovina and Croatia without power.
The report identifies seven direct causes whose coincidence on that day led to the power outage:
Crnogorski Nearly simultaneous fault (with only a 13-minute in between) on two critical transmission lines in the region – the 400kV Ribarevine–Podgorica overhead line and the 400kV Zemblak–Kardia overhead line
Crnogorski Inability of transmission system operators in the region to detect system inadequacies in the period between the two faults
Crnogorski Failure to detect voltage instability in the region
Crnogorski Cascading outage of three additional overhead lines due to overload protection settings
Crnogorski Automatic response of transformer tap changers to the disturbance
Crnogorski Insufficient amount of available reactive power across the entire region
Crnogorski Lack of preventive measures against voltage collapse in the region
Based on the identified causes, the report provides 12 recommendations for improving the operation of all interconnected transmission system operators:
Crnogorski Review of national policies and processes for vegetation removal in overhead line corridors
Crnogorski Improving observability areas in monitoring and control systems
Crnogorski Conducting regular voltage stability assessments
Crnogorski Identifying key indicators that signal the risk of voltage collapse
Crnogorski Revising ENTSO-e guidelines for overload protection settings
Crnogorski Blocking automatic voltage regulation in specific situations
Crnogorski Assessing the adequacy of resources for voltage control
Crnogorski Evaluating the feasibility of introducing automatic voltage regulation measures in pre-failure conditions
Crnogorski Assessing the possibility of installing undervoltage protection for controlled automatic disconnection of certain consumers from the grid
Crnogorski Verifying the accuracy of data used for security analyses
Crnogorski Timely updating of information on system element availability
Crnogorski Checking the accuracy of voltage condition calculations in the region
Along with previously issued recommendations from past incidents within the ENTSO-e area, these measures aim to reduce the likelihood of similar incidents occurring in the European electricity interconnection.
The full report, which involved contributions from over 60 experts across Europe, can be found here:ENTSO-E Report