The contribution of the revitalization of submarine cables 110 kV to resilience of the southern part of the Croatian power system

Having reviewed the Croatian islands in the Adriatic Sea and classified them according to their size (large islands, islets and ridges) and the population (inhabited, not inhabited and periodically inhabited), details are given in the paper on development of a part of the electric power system on the Adriatic islands conditioned by historical differences. The electric power system on the islands in the past focused mainly on electricity generation in small power stations for local needs. The oldest power station was built on 1902 in the North Adriatic area, on the island of Rab. In the South Adriatic area the power station was built on 1928 on the island of Korcula. Since the paper primarily considers the high voltage cables 110 kV, the cables installed from 1968 to 1988 on Adriatic Sea area are described herein. All the cables are low-pressure 3-core oil-filled submarine cables (LPOF). At the beginning of 21st century, considering the age of oil-filled cables and unfavorable oil properties and taking into account the ecological approach to the matter, discussion about replacement of oil-filled submarine cable is started. Due to the cost optimization, selection of the cable type was subject to technical and economic analysis. The analysis outcome was the selection of a 3-core Cu 1×3×630 mm2 cable with double steel armor. When the type of cable was chosen, the development of design documentation and obtaining the building permit is launched. In the paper will be considered the replacement of all types of cable: cable 110 kV Dugi Rat-Postira, cable 110 kV Crikvenica-Krk, and cable 110 kV Hvar-Korcula including the sections marked. Because the building permits have been obtained, some works on the Mainland-Island of Brac cable link 110 kV are executed. Any further activities are conditioned by getting all the permits required and execution of all preparing activities. The main investor's intention is at the same time purchase as many cables as possible, because the transportation costs are the same regardless of the quantity of submarine cable 110 kV. The procedure should be expedited because of a fault that occurred on the Mainland-Island of Krk section.