We are starting reconstruction of one of the most important switchyards in Lithuania

Energy independence will be achieved not only by synchronisation projects approved by the Government, but also by planned modernisation works of the electricity network and its elements. In the middle of June, Lithuanian electricity transmission system operator Litgrid began reconstruction of the 330 kV switchyard at Kruonis Pumped Storage Hydropower Plant (PSHP) transformer substation. This is one of the operator's largest reconstruction projects in recent years. 

The Kruonis PSHP switchyard has a significant impact on the reliability of the entire national power grid and the project of synchronisation with continental Europe. 

“The switchyard is an integral part of the currently constructed “electricity transmission highway of Western Lithuania”. This system of lines and substations, which stretches from Darbėnai to Kruonis, will improve the access of consumption-intensive Eastern regions to electricity produced by offshore wind parks and received through the future offshore interconnector Harmony Link.” says Rokas Masiulis, Litgrid CEO. 

The new construction in Kruonis will have an impact on one of the key Synchronisation projects: construction of 330 kV overhead line Kruonis PSHP–Bitėnai. 

The second phase of this project is currently being implemented with construction of a new 62 km long single-circuit 330 kV overhead line from Kybartai to Jurbarkas, which will connect with the 330 kV lines Jurbarkas–Bitėnai and Kruonis PSHP–Sovetsk. Installation of foundations and construction of supports for the lines began in May. The implementation of the Kruonis PSHP–Bitėnai project will enable the disconnection of the line going to Sovetsk (Kaliningrad region) after synchronisation with the continental Europe. 

During the reconstruction, a separate connection bay for the Kruonis PSHP–Bitėnai line will be prepared in the switchyard, which is necessary to activate the line and to complete the entire project. 

To continue the construction of the overhead line, enable the reconstruction of the Kruonis PSHP switchyard, and at the same time ensure the reliability of the electricity transmission network, Litgrid is currently completing the installation of a temporary connection in Kruonis. It will work until the new Kruonis PSHP–Bitėnai line is activated. 

The modernized switchyard will also enable the development of Kruonis PSHP. One of the country's most important power plants, which can provide fast reserve power and thus contribute to ensuring the stability of the network, will be expanded with the fifth hydro pumping unit. 

This unit will have a maximum capacity of 110 MW with a minimum of 44 MW in generator mode and a minimum of 77 MW in pump mode. Ignitis gamyba, the operator of the plant, announced that the overall efficiency of the cycle will reach about 78.6%, and the lifetime of the unit will be 40 years. The new facility will expand the scope of the power plant's capacity utilization, allow the power plant to participate more effectively in the common Baltic balancing market and ensure greater competitiveness by providing additional system services. In addition, the new unit will help to balance the rapidly developing but fluctuating generation of renewable energy sources in Lithuania. 

It is planned that the fifth unit will be installed and start operating by the end of 2025.  

During the reconstruction of the Kruonis PSHP 330 kV switchyard, the fourth generator of the plant will be separated from the first three to another connection in the substation, thereby increasing the reliability and flexibility of the power plant, reducing the risk of losing the energy of all generators in the event of a short circuit. The substation will also be ready to connect the fifth generator planned in the future. 

During the renovation of the substation, all the primary devices of the 330 kV switchyard will be replaced, and the section of the overhead line from the 330 kV switchyard to the first autotransformer will be reconstructed. 

Kruonis PSHP transformer substation was commissioned in 1988. A total of 13 connection baysare operated in its 330 kV switchyard. 

The reconstruction of Kruonis PSHP substation will cost 52 million euros, it will be implemented in stages until 2026, taking into account the synchronisation programme projects and the development plans of Ignitis gamyba. 

The text was published in the June issue of the Synchronisation newsletter.