EstLink 1 cable shutdown for annual maintenance this week
The impact of a shutdown of the EstLink 1 undersea electricity cable, which links Estonia and Finland, is likely to be much less in late summer than if the work was done in winter, grid distributor Elering said.
The cable is undergoing scheduled annual maintenance from Monday to Friday.
Electricity consumption is lower and the share of renewable energy production is higher at this time of year, making it a logical time to carry out the work, rather than during the winter months when reliance on the EstLink 1 connection is higher, Elering said.
Additionally, a lot of the maintenance involves outdoor work, which is more convenient, faster, and more cost-effective in summer than in winter.
Head of the EstLink unit Reigo Haug noted that the regular maintenance of the EstLink 1 cable is in any case unavoidable.
"Preventive maintenance is necessary to ensure the reliability of equipment throughout its lifetime, and to assess the condition of the installation and perform both scheduled regular interval maintenance and works to prevent emergency repair needs," Haug said.
"We will be carrying out EstLink 1 maintenance in a combined interval-, condition- and fault-based manner. Those maintenance works which require the entire link to be switched off take place once a year, and usually last five to seven days. The maintenance is being carried out simultaneously at the stations on both the Estonian and Finnish sides of the connection," Haug continued.
This year's maintenance will include work on high-voltage alternating and direct current switchgear, transformer area, reactor rooms, and converters.
"In addition, we maintain the converter's cooling, auxiliary power, and ventilation systems, as well as control, protection, and measurement systems. This year, particular attention is given to the modification works of the auxiliary power system of the Harku converter station and the maintenance of the converter transformer," Haug added.
The 350MW EstLink 1 cable was completed in 2006 as a commercial project by both Baltic and Finnish energy companies and has been under the ownership of Estonian grid distributor Elering since 2013.
The 650MW EstLink 2 cable opened in 2014, while a planned EstLink 3 connection is at the impact assessment stage and not likely to be completed until the next decade.
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Editor: Andrew Whyte, Urmet Kook
