Harmonic Measurement, Analysis And Mitigation To Improve Power Quality At A Petrochemical Complex

A contract was awarded to carry out Harmonic Measurement, Analysis & Mitigation to improve power quality in Petrochemical Units 1 and 2 of a large Petrochemical Complex in Uttar Pradesh, India. The evaluation of harmonic measurements and recommendations for mitigation measures was required to be based on the standard IEEE 519: 2014.

The scope of work included the following activities:

  • Site data Collection
  • Real time measurement of voltage and current harmonics (at various test points using ‘Class A’ Power Quality (Analyzer)
  • Constant interaction with client for technical discussions
  • Software simulation for of Harmonics and data verification against site measurements
  • Software based Harmonic Analysis
  • Recommendation of Mitigation measures to improve power quality in the Petrochemical complex


As per the contract scope of work, the project was to be carried out in three phases:

Phase1: Data collectionMeasurement of all Electrical parameters like Voltage, Current, kW, Power Factor, neutral current, THD Voltage, THD Current Harmonic and Individual harmonics levels (up to 50th) at the incomer end of panels.
Phase2: AnalysisAnalysis of the harmonic readings as per IEEE 519-2014 standard with standard software and provide the recommendations to improve power quality, power factor improvement, and reduction in harmonics levels to comply with IEEE 519-2014 standards.
Phase3: Report Submission& PresentationDetailed study report with workable solution (backed by software simulation results) to minimize the impact of harmonic distortion subject to the maximum limits per IEEE 519-2014. Input to detailed implementation plan along through drawings and detailed specification of equipment such as harmonic filters and necessary supporting calculations, bill of quantities and cost estimate etc.

Soon after project award, iFluids engaged the client in technical discussions and proposed a schedule for the site survey and harmonic measurement activities that were required to be carried out. The schedule considered site survey for approximately 3 weeks.

Internationally proven equipment of ‘Fluke’ make was deployed for conducting real time harmonic measurements at site. Following the completion of site survey, Single line diagram was created for the project, which was a complex task in itself since there were more than 30 substations and more than 150 measurement points to be covered for the harmonics study. Considerable interaction with client was required in the post site visit stage for completing the model since reasonably adequate and accurate technical information for various pieces of plant equipment were required that were not readily available upfront or at the time of site survey.

Although measurements were carried out up to the 50th order harmonic, a joint decision was taken with the client to restrict the reporting and analysis to 25th order harmonic since it is observed that the harmonic content is negligible beyond the 25th order harmonic.

Subsequent to in-house analysis and calculations, a detailed technical report tabulating the measurements taken, discussion on the deviations observed between computed THD values and prescribed limits of THD as per IEEE 519: 2014 and recommended mitigation measures through installation of active harmonic filter banks was prepared and forwarded to the client.


It was observed that although THD variations did exist with respect to the standard, the same were not large enough to warrant immediate corrective action or cause abnormalities in plant operations.Mitigation measures included installation of active harmonic filters at LV level as this arrangement results in low cost solution for elimination/significant mitigation of harmonics in the system.