Adjustable-speed drive retrofit for Ormond Beach FD fans

The boiler on Southern California Edison's 750 MW Ormond Beach Unit 2 was extensively modified to reduce minimum load from 250 MW to 36 MW. With the unit operating at minimum load frequently at night, it became economically attractive to install adjustable speed drives (ASDs) on each of the 6250 hp forced draft fan motors. The authors describe the application concept that has evolved from the EPRI tests, the specific development features in the new ASDs field test results of power savings, measured harmonics at the utility bus and at the motor, the effect of THD reduction by using an input harmonic filter, and operating experience. Fan inlet vanes have been removed, and no ASD bypass was provided.<
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