The isolated operation of the Baltic states

31.08.2017. The feasibility study on the isolated operation of the Baltic States has been finalised by the end of August 2017. The study has been ordered by Litgrid, AST and Elering, the electricity transmission system operators of respectively Lithuania, Latvia and Estonia, and prepared by the international consulting company Tractebel Engineering S.A.

The feasibility study on isolated operation of Baltic States launched in January 2017 and finished in August 2017, analysing the capability of the power systems of Baltic States to operate in isolated mode. The study analysed the technical, legal and economic aspects of the isolated operation of the Baltic States.

The performed study established a set of technical requirements and guidelines in order to prepare and perform an isolated operation test of the Baltic States power system. These guidelines provide an overview and timeline of the additional investments, studies and trainings to be performed before the test. The validation of generating units and system dynamic behaviour with PMU measurements is considered to be a key aspect in the test preparations. The direct and market costs of preparing and executing the isolated operation test have been calculated. A legal analysis of the possible obstacles has been presented.

An isolated operation test of the Baltic States power system is challenging, but possible taking into account the technical recommendations made in the power system dynamic analysis report and the requirements and guidelines for the isolated operation test. In these reports several scenarios have been analysed with different load levels in all Baltic countries, with and without HVDC connections and Kaliningrad region. Based on the static and reliability analysis performed, the summer period has been identified as the most suitable period to conduct the isolated operation test. Amongst others, technical recommendations have been made by consultant on the primary and secondary reserve provision and the set of must run units, to guarantee frequency stability after credible contingencies. Special attention during the test has to be paid to the maximum power infeed requirements and the generating units minimum power output.

Essential to a successful isolated operation are dispatchers trained to handle the changing system behaviour during isolated operation. These trainings should especially focus on managing frequency stability with changing load, maintaining reserves, islanding and resynchronisation procedures and emergency operation.

No major legal or regulatory obstacles against isolated operation have been identified and a set of recommendation has been composed in order to overcome any.

Finally an 18 hours test duration with several generation and load rejection tests is recommended in the summer of 2019 over the time window 10pm to 16pm the next day.

After the decision on the exact date of Isolated Operation Test, Market Participates will be informed following standard Nord Pool procedures.