The Al-Fadhili back-to-back HVDC station is a back-to-back HVDC connection between Saudi Arabia, whose grid operates at 60 Hz, and its neighbouring Gulf states which have 50 Hz grids.
[1] The station is located in Saudi Arabia, approximately 100 km north-west of Dammam, but was built for and owned by Gulf Cooperation Council Interconnection Authority (GCCIA).
GCCIA is constructing a 400 kV, 50 Hz AC transmission line to interconnect Kuwait, Bahrain and Qatar through Saudi Arabia.
Each pole has nominal DC voltage and current ratings of 222 kV, 2776 A.
The converter poles are normally kept blocked but the control systems continuously monitor the frequencies of the two grids and, upon detection of a sudden change of frequency, deblock one or two poles as needed to restore the shortage of power.