Harmonic experiences with a large load commutated inverter drive

The paper illustrates the use of a high pass filter for reducing troublesome harmonic distortion caused by a large load commutated inverter (LCI) drive at a large petrochemical plant. Actual field measurement data of the 12.47 kV distribution system of the plant is given to show the harmonic distortion that was causing operational problems. The harmonic system impedance derived from these measurements was used in the development of an accurate harmonic analysis computer model. This harmonic model was then used to evaluate the application of a high pass filter to reduce harmonic distortion. Actual field measurements were then made after the installation of the high pass filter to verify the results of the simulations. The tools used for this paper included a harmonic analyzer, an oscilloscope, a harmonic simulation program, and an electromagnetic transient simulation program. The results of this investigation lead to proposed improvements to IEEE Std 519