At Sikassaare substation in Saaremaa, two 40 MVA power transformers were installed in the 110 kV distribution system, providing reliable electricity supply to the island with redundant reserve capacity. The dual installation meets the strict supply security requirements of island regions.
Saaremaa's power grid is a system dependent on the mainland main connection, where the impact of substation failures is significantly greater than on the mainland. The installation of two 40 MVA transformers at Sikassaare substation ensures that no single equipment failure will interrupt the power supply — the other unit takes over the entire load. This n-1 security of supply level is particularly critical for an island connection.
Work was carried out under challenging logistical conditions, taking into account the specifics of Saaremaa's isolated location. Sea transport of transformers and subsequent overland transport required special arrangements. Local subcontractors were engaged for installation works, and the commissioning process was carried out in accordance with Elering requirements, ensuring simultaneous start-up of both units in production mode.
