Power-factor correction supply after two failed capacitor banksPower-factorcorrectionsupplyaftertwofailedcapacitorbanks

The plant had bought capacitor banks twice in six years. Both failed within eighteen months — both were undetuned banks sized purely on the power-factor penalty and bought on price.

The unit ran several hundred variable-frequency drives, but nobody had measured the resulting harmonic spectrum before specifying correction.

The utility penalty was material, and the client had begun to assume power-factor correction simply did not work in their environment.

We logged the supply for seven days before quoting. Fifth-harmonic distortion measured 6.8%, and the old bank was resonating close to the fifth harmonic — amplifying the very current that destroyed it.

We supplied a twelve-stage 1200 kVAr panel with 7% detuned reactors and heavy-duty capacitor-rated contactors, all genuine, authorised-channel product matched to the measured spectrum.

Stage-level current monitoring was included so a capacitor losing capacitance is flagged long before it fails visibly.