Some peculiarities in insulation coordination and mitigation measures against extreme sea salt pollution on Croatian 110 kV 'Islands connection'

摘要

Among Croatian transmission lines (rated voltages of 110 kV, 220 kV and 400 kV) one combined 110 kV line (OHL + submarine cables) is particularly interesting due to its characteristics and environmental influences to which it is exposed. It is s.c. "110 kV Islands Connection" (see Fig. 1), a combination of overhead lines and submarine cables between great towns Rijeka and Zadar on Adriatic coast passing over great islands Krk, Rab and Pag (with one branch over islands Cres and Losinj) in total length of about 170 km (including about 30 km of 4 sections of submarine cable). There are four 110 kV "passing or tapped type" substations on islands (RP Omisalj, TS Rab, TS Pag and TS Nin), two "meshed type" substations (TS Krk and TS Novalja) - all in AIS version - and eight 110 kV s.c. "cable houses" or "cubicles" (transitions: submarine cable - OHL) with 110 kV bushings. High voltage equipment - particularly outdoor insulators - in open space and even in "cable houses" are exposed to extreme sea salt pollution from the nearby Adriatic Sea.