Abstract :
The isolated power system for Abu Dhabi, UAE, consists of 200 kV, 132 kV and 33 kV transmission network, supplying the 11 kV and 415 volts distribution substations. This power was generated by a mixture of gas turbine (30-40% of spinning machines) and steam turbines of various capacities ranging from 15 MW to 160 MW. At low or medium load condition the largest unit (160 MW) or even the next largest unit (85 MW) can constitute about 15% to 20% of the spinning generators. Therefore, in the absence of proper emergency control strategies, the trip of a large unit can cause the system frequency to fall below the acceptable levels, and endangers the system operation
