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During testing, NordBalt and LitPol Link will be prepared to serve for decades

During testing, NordBalt and LitPol Link will be prepared to serve for decades

The system tests of the interconnections NordBalt and LitPol Link are going ahead full speed. Because of a complicated high voltage direct current (HVDC) technology, time consuming tests need to be repeated several times. These interconnections with Sweden and Poland are the most sophisticated technologies installed in the Lithuanian power system.
The testing of interconnections is a long and difficult process, which begins in the factories where the equipment is mounted, then testing it at the site and finally putting the interconnection into the trial operation. The first tests of LitPol Link and NordBalt were carried out more than a year ago, when the computerised control system and safety systems were assembled. 
When the final construction works are completed, separate elements of the interconnection are tested: the overhead lines or cable, transformers, cooling system, the equipment of HVDC converters, etc. All functions and different operational modes are tested because all parts of the link must work together correctly. During the system tests, electricity must be transmitted in both directions. The next stage of the tests only begins when a specific parts of the interconnection works perfectly, and all system commands are managed correctly.
During the trial operation, the interconnections are operating according to the principles of free and competitive electricity market, and the electricity is flowing in the direction of the highest price. However, the interconnection managers determine daily capacities and the interconnection is operating in this mode for a few weeks to a few months as needed.
The NordBalt interconnection will operate using the newest high voltage DC technology. At both ends of the interconnection the fourth-generation converters with flexible control opportunities are built. The HVDC back-to-back converter station of LitPol Link is unique in the Baltic countries since the interconnection is controlled in a single centre in Alytus, rather than both ends of the power line. The similar HVDC back-to-back converters need to be built on the Lithuanian border with third countries when the project of the Lithuanian power system synchronization with Western Europe is prepared for further implementation. 
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