| Al-Fadhili back-to-back HVDC converter station | |
| Country: | Saudi Arabia |
| Owner: | Gulf Cooperation Council Interconnection Authority (GCCIA). |
| Substation Installer: | Areva T&D |
| Est: | 2009 |
| Type: | Back to Back |
| Current Type: | HVDC |
| Length Km: | 0 |
| Capacity: | 3 x 600 MW |
| Dc Voltage: | 222 kV |
| Poles No: | 3 |
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). The converter station was built by Areva T&D, now Alstom Grid, between 2006 and 2009.
GCCIA is constructing a 400 kV, 50 Hz AC transmission line to interconnect Kuwait, Bahrain and Qatar through Saudi Arabia. Later phases will also connect Oman and United Arab Emirates. The Al-Fadhili HVDC system allows power to be exchanged between the 50 Hz GCCIA system and Saudi Electricity Company system.
The converter station consists three identical poles, each with a nominal power transmission rating of 600 MW and an overload rating of 660 MW. Each pole has nominal DC voltage and current ratings of 222 kV, 2776 A.[1]
Unlike most HVDC systems, which are designed to be used more or less continuously for transmission of power, the Al-Fadhili system is normally intended to remain in standby mode, only transmitting power between the two systems after a major loss of generation in one system. 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. This allows Spinning reserve to be shared between the two system and as a result the concept is known as Dynamic Reserve Power Sharing (DRPS). With a total power rating of 1800 MW, the Al-Fadhili system was, on completion, the largest HVDC back-to-back system in the world [2] and the first HVDC system in the Middle East.