Multiple Harmonic Filters Over 6 Phases of Expansion in a 170 MW Plant

Experience gained during the growth of a chemical manufacturing facility from a 65 MW to 170 MW load in multiple stages is presented. Large filter banks are required to control harmonic current and provide reactive power compensation for the rectifiers that energize the chemical process. As the load grows and the filters become large, utility generated harmonics are drawn into the filters resulting in difficulties complying with IEEE 519. The large size of the filters creates voltage rise issues for local equipment and the transmission system on load upset. Filters stress due to utility capacitor switching and in-plant filter element switching is compared for the initial load stages and the final load stage. Filter stress is reduced as the number and size of the filters is increased.