Litgrid

To install a system that would ensure the frequency stability of the Baltic electricity system in the event of an unforeseen disconnection from the mainland European grid and the Baltic electricity system operating in island mode.

Significance of the project

On 27 May 2019, the Baltic transmission system operators signed an agreement with the continental European operators on the synchronization of the Baltic electricity systems with the continental European networks.

Synchronisation with the Central European Synchronous Area (CESA) is the last step towards Lithuania’s energy independence. Currently, our electricity system is still dependent on frequency control in Russia, but already in 2025, it will operate in one synchronous area together with the systems of other European countries.

The signed agreement sets out a catalogue of technical measures that need to be implemented in order to start synchronous work. As the Baltic States will be connected to the continental European networks synchronously only via the LitPol Link double-circuit line, the catalogue stipulates that the Baltic transmission system operators must implement a frequency stability assessment system that will ensure the frequency stability of the Baltic electricity system in case of unforeseen disconnection and the Baltic electricity system should operate in island mode.

General project information

The newly implemented Frequency Stability Assessment System (FSAS) will consist of four modules:

1. Planning module

This module will perform an interference analysis during the planning process and check that the established limits of frequency change rate and frequency change are not violated after evaluating the planned data of the Baltic systems.

In case the frequency stability limits are violated, FSAS will provide corrective factors.

2. Interactive (online) module

This module will perform interference analysis and determine whether the frequency stability limits have been violated by evaluating the readings of real-time measurements of the Baltic systems (generation, demand, flows through HVDC connections).

If the frequency stability limits are violated, FSAS will provide corrective factors.

3. Analysis module

Using archived data, a freely configurable mode is created for engineering staff to perform mode analysis. If frequency stability limits are violated, FSAS will provide corrective factors.

4. Real-time monitoring module

The purpose of this module is to monitor the inertia of the Baltic power system and the status of Baltic synchronous operation.

The implementation of the project is planned in two stages:

In the first stage, the FSAS technical specification will be prepared with the help of consultants - network operator of continental Europe, which will include setting requirements for system architecture, cyber security, integration with existing IT systems, determining signal volumes, computing model.

In the second stage, FSAS will be designed, installed and tested according to the prepared technical specification.

Work calendar

Activities	Date of implementation
Agreement signed with a consortium of continental European operators according to the terms of reference prepared by Litgrid and agreed with Baltic operators	16 April 2021
The final study report received	2022 Q3
Procurement of FSAS development and implementation services	2023 Q1
Agreement on the FSAS development and deployment services contract	2023 Q4

Project financing

The project is co-financed from the Connecting Europe Facility (CEF).