A 479 km long 750 kV transmission line was put into exploitation between Hungary and Ukraine in 1979 in order to create a strong connection between the Hungarian power system and the Russian-Ukrainian EHV grid. The line was planned for the transmission of nearly 2000 MW active power. A reconstruction was effectuated in the Hungarian
The initial ovewollage protection afAlbeltina substation
Fig 1
550 kV substation (Albertirsa) in the middle of the eighties, based on the experiences of the initial operation. The 750 kV line was put out of operation in 1993 due to the political and economical changes. Alter a long interruption the line has restarted to operate in spring of 2002. The present system configuration significantly differs fiom the old one: the supply system in the Ukrainian side became weaker and the transmitted power lower. The line constmction and the substation equipments have been modified to some extent. The new situation necessitated a revision of controlling the reactive power, the overvoltage protection and the efficiency of reclosing automation. The paper reports on the studies, which preceded and prepared the ahove-mentioned modifications.