Saudi Aramco experience — Islanding scheme for Manifa Central Processing Facility

Manifa Central Processing Facility (CPF), the fifth largest oil field in the world, is connected by 25 manmade islands and 20 kilometers of causeways. The current production capacity of heavy crude oil at the CPF is 500,000 barrels per day (bpd). The full production capacity of the plant is 900,000 bpd, which the facility will meet in 2014. The power plant generation includes two combustion gas turbine (CGT) generators and two heat recovery steam generators (HRSGs) providing steam to two steam turbine generators (STGs), with a total generation capacity of about 500 MW. Two tie lines at 115 kV connect the Manifa CPF to the external utility system. A power management system controls the Manifa CPF frequency once the Manifa CPF islands from the external grid. Some of the severe external disturbances require Manifa islanding operation in less than 15 cycles to maintain system stability. This very critical CPF requires the ability to quickly identify an islanding condition correctly. This paper discusses the islanding scheme design details for local and remote signals. For significant power exchange with an external grid, local measurement-based islanding can correctly and quickly identify the islanding condition.