18-03-2014, 12:25 PM
AES Buffalo Gap Wind Farm Buffalo Gap 2 - 232.5 MW 155 – GE 1.5 sle
AES Buffalo Gap
Wind Farm
Three Phases totaling 524.3 MW
Summary:
Located in Taylor and Nolan Counties SW of Abilene.
Buffalo Gap 1 – 67 Vestas V-80, 1.8 MW turbines totaling 120.6 MW, COD late/05
Buffalo Gap 2 – 155 GE 1.5 sle, 1.5 MW turbines totaling 232.5 MW, COD early/07
Buffalo Gap 3 – 74 Siemens 2.3 MW turbines totaling 170.2 MW, COD mid/08.
Interconnected to AEP Bluff Creek at 138 kV via project owned 12 mile 138 kV T/L.
GE 1.5 sle Turbine
Method of starting
When the wind in the area increases above the cut in speed (3.5 m/s) the turbine blades are pitched from “feather” to “power” and the wind begins to turn and accelerate the rotor. Once the rotor achieves operational speed of 10-11 rpm the turbine is softly connected to the line with a ramp up of the power electronics.
Method of controlling power output
Output power is regulated through a combination of variable blade pitch for control of rotor torque, and variable frequency control of the generator to control drive train speed and torque. During a wind gust the rotor frequency is increased and the drive train is allowed to accelerate while reduging torque to “store” the gust power spike as kinetic energy in the rotor like a flywheel. Once the gust passes the controller extracts the power in the rotor and slows it back to the nominal speed.
Method of stopping
For normal shutdown the rotor blades are pitched to feather. For an emergency shutdown the blades are pitched to feather (battery back-up if required) and a disk brake is engaged on the high speed shaft.