site.btaJuly 20, 1975: Electricity Systems of Bulgaria, Turkey Connected under Electricity Exchange Agreement

On July 20, 1975, Bulgarian State Council Chairman Todor Zhivkov and Turkish Prime Minister Suleyman Demirel participated in a ceremony marking the connection of the two countries' electricity systems  at Adrianople, Turkey.

The construction of the 400-kV transmission line linking the energy systems of Bulgaria and Turkey continued for three years and was carried out in implementation of the agreement signed in 1969 and the agreement reached in 1974 on the exchange of electricity via the Maritsa East - Babaeski power line. The designs for the transmission line were prepared by the Energoproekt team in Sofia, and the 152 P-shaped posts on Bulgarian territory were manufactured in the metal construction plants in Karnobat and Tvarditsa and installed by workers of the Transformations and Power Lines Department. On Turkish territory, the voltage was transformed by the 213-ton transformer at the Babaeski substation, manufactured at a plant in Sofia.

According to the 1974 agreement, by the end of December 1975 Bulgaria had to supply Turkey with 25 million kWh of electricity, and in 1976 with another 50 million kWh, and Turkey had to supply Bulgaria with 75 million kWh of power.