Research Article · SUSTAINABLE DEVELOPMENT
Resilience of the Power Grid in Southeast Europe in the Context of Coordination and Balance
KSI Transactions on Knowledge Society · Vol. XVII · No. 1 · pp. 26–30 · 2026
Abstract
Bulgaria, Romania, Greece, Croatia and Slovenia lie at the south-eastern edge of the Continental Europe synchronous area, where the system split of 8 January 2021 started and where a voltage collapse blacked out large parts of four transmission systems on 21 June 2024. This paper reviews how the five systems are tied into the European arrangements for frequency control, cross-border balancing and regional coordination, using EU network codes, ENTSO-E and ACER documents and peer-reviewed studies up to October 2026. All five TSOs take part in imbalance netting. Romania and Croatia are not yet connected to the aFRR platform, and on the mFRR platform only Slovenia operates in normal mode. Neither disturbance was traced to a lack of balancing reserves; the investigations point to large flows, undetected overloads and missing voltage support. A framework is proposed that places ancillary services in the phases of a disturbance and defines five dimensions for comparing the systems.
Keywords: ancillary services, power system resilience, electricity balancing, TSO coordination, Southeast Europe
Subject classification
How to cite
APA 7 — bibliographic citation based on the published issue
Full text and references
Download the individual article PDF to read the complete methods, results, discussion, conclusions and bibliography. HTML full text and a structured reference list may additionally be provided.
Open article PDF ↗Article history and integrity notices
Published. Any correction, expression of concern or retraction must be displayed here with a dated formal notice. Article history dates should be added only after verification against editorial records.
Display after checking the editorial records.
Display dated notices prominently and link to the formal record if applicable.
Copyright and licence
© 2026 Kiril Anguelov. Published by the Knowledge Society Institute in KSI Transactions on Knowledge Society.
Creative Commons Attribution 4.0 International (CC BY 4.0): view licence.
The actual copyright holder and any third-party exceptions must be verified in the editorial record and identified on the live article page and in the article PDF.