On the order of the three transmission system operators (TSOs) of the Baltic States - AS "Augstsprieguma tīkls" of Latvia, "Elering" of Estonia and "Litgrid" of Lithuania, the consortium of European transmission system operators has conducted five studies, providing answers to questions about the management of the electricity transmission systems of the Baltic States after their upcoming connection to the synchronous power grids of the continental Europe.

Under the framework of the studies, mathematic simulation studies were made for the forthcoming operation of the electricity transmission grids of the Baltic countries and a set of necessary actions were investigated to fulfil the technical requirements for synchronous operation with the European network. In total, five studies have been carried out, including a study of power system dynamic angle stability and a study of the small signal stability with the full dynamic model of the electricity transmission grids of Baltic countries and continental Europe, a study of the isolated operation of the power systems of the Baltic countries, a study of the evaluation system of the frequency stability of the power systems of the Baltic countries, as well as a study of the implementation of the load-frequency control system in the electricity transmission systems of Baltic countries.

The list of the aforementioned synchronization studies was defined in the connection agreement (CFI Agreement – Agreement on the conditions of the future interconnection of power system of Baltic States and power system of Continental Europe) concluded on May 27, 2019 between the TSO`s of the Baltic States and the TSO`s of the Continental Europe, see appendix II. The scope and necessity of the studies required for synchronization was determined by the Regional Group of Continental Europe (RGCE) of the European Electricity Transmission Operators Association ENTSO-E, to ensure that the synchronous operation of the electricity transmission systems of the Baltic States will contribute to the reliability of the operation of the electricity systems of continental Europe and to assess the ability of the electricity transmission systems of the Baltic States to fulfil all the requirements of continental Europe for the operation of electricity transmission systems.

Synchronization studies were conducted by a consortium of TSOs of continental Europe, in which TSOs from Poland - Polskie Sieci Elektroenergetyczne S.A., from Germany - 50Hertz Transmission GmbH and Amprion GmbH, as well as - Elektromreža Srbije from Serbia has participated. The consortium has adequate, specific and special knowledge about the operation of electricity transmission systems of continental Europe, therefore, on the recommendation of ENTSO-E, the consortium was considered as a source of competence for conducting the research and providing consultations in order to fulfil the requirements specified in the catalogue of technical measures of the accession agreement. The total cost of research is 3.4 million EUR, which was covered in equal parts by the TSOs of the Baltic States.