CIGRE Study Committee B1 - Selected Topics of Power Cables Used in Offshore Wind Farms

A. Rakowska (Poznan Univ. of Techn., Poland)

The dynamic development of offshore wind energy and plans for its further development mean that in the works of CIGRE you can find more and more various types of publications on cable lines for offshore wind farms. The most important are the Technical Brochures, and the first TB 610 on this topic "Offshore generation cable connections" (180 pages) was published in 2015. In the same year, TB 619 "HVDC connection of offshore wind power plants" (100 pages) was published too. During the last CIGRE Session 2022 as part of the Study Committee B1 Power cables Discussion Meeting – 5 papers were related to the topics of offshore cables, and 11 to submarine cables - and export cables are submarine cables. CIGRE has published 9 Technical Brochures on submarine cables since 2009. The latest TB 833, published in 2022, is “Installation of Submarine Power Cables” (241 pages). And one of the first is TB 490 "Recommendations for testing of long AC submarine cables with extruded insulation for system voltage above 30 (36) to 500 (550) kV" from 2012 - which of course also includes after-installation tests. It is worth to notice that this brochure also includes the following sentence: “…in addition to standard test methods using alternating voltages, there also exist some other type of voltages for on-site testing, such as direct voltage and damped alternating voltage. However, DC tests should be avoided for AC extruded cables”. The next CIGRE TB 623 (published in 2015) was concerned to "Recommendations for mechanical testing of submarine cables", because the mechanical resistance of cables is an extremely important parameter, and proper mechanical strength of submarine cables is necessary not only during operation, but above all, during the installation of lines and transport . The same topic, but for cables for dynamic applications, is described in TB 862 of 2022 "Recommendations for mechanical testing of submarine cables for dynamic applications". In 2018, the scope of the proposed additional tests of submarine cables was presented in TB 722 "Recommendations for additional testing for submarine cables from 6 kV (Um = 7.2 kV) up to 60 kV (Um = 72.5 kV)". CIGRE TBs have also been published with information about both types of cables – for underground and submarine use. It is worth mentioning, for example, TB 773 “Fault location on land and submarine links (AC & DC)” from 2019 and TB 815 Update of service experience of HV underground and submarine cable systems from 2022. The content of CIGRE TB is always the result of the work of many prominent experts in a given field, representing various countries, who already have some experience and knowledge about a given problem and it is a guide because TB contain full information about the current level of knowledge on a given topic, and it is a kind of instructions for the correct proceeding with e.g. power cables and cables lines, scopes of required tests and review of applicable international standards.