Power quality investigation, field measurements and harmonic analysis to improve production at a new chemical products facility

Preliminary engineering studies and analyses are conducted during the design phase of a project to verify the equipment selection and detect potential issues that may arise after installation. Conservative assumptions and typical data normally used in the preliminary engineering often do not reveal inherent design flaws until startup and commissioning take place. Consequently, design changes must be field installed to alleviate the malfunction of the electrical distribution equipment. Such was the case at this new chemical products facility, which experienced production levels well below design targets shortly after startup, resulting in significant financial losses, because power quality issues were overlooked during the preliminary system analysis. By conducting power quality field measurements and investigation, the authors captured multiple power quality problems, including excessive current and voltage harmonics, voltage sags, elevated rate of voltage rise (dv/dt), and utility capacitor switching disturbances. The authors engineered several solutions to remedy the aforementioned power quality problems, discussing the advantages and disadvantages of each, before arriving at the optimal solution. The paper demonstrates that the complexity of the electrical distribution system, as well as the predicted harmonic loading, dictate the detail and accuracy required for the preliminary analysis. Additionally, the paper provides guidelines for closely examining the power quality and harmonic distortion to improve future engineering studies and analysis performed during the design phase.