Power Quality Analysis
The introduction of steel radial tyres brought in considerable non-linear loads (NLL) in the forms of variable speed drive (VSD), DC drives and sizeable SCADA and HMI controls in the tire manufacturing process. Premier tyre companies complying with safety regulations upgraded their process for high quality and long life radials, which further increased PLC and HMI control. It resulted in an increased total current harmonic distortion (THDi) which at the base level, without switching on capacitors, was between 20 to 40% at the main incomer of various process transformers with a corresponding total voltage harmonic distortion (THDv) of between 5 to 10%.
Factory engineers need to maintain Power Factor (PF) for avoiding high demand (kVAh) charges and low PF penalty from the utility company. But they faced a new problem in adding capacitors either at load end across various high capacity motors or at PCC loads or centralized APFC panel across transformer LT busbar. It magnified harmonics in an unpredictable and non-linear manner. The magnification could be as high as several times the base harmonic level or just a few percentage point higher, which depends upon the fault level of the power system. In a high fault level power system, THDi magnifies disproportionately higher than THDv. The reverse happens with a low fault level power system.
Then arrived the Detuned Harmonic Filter with a 6% reactor in series with the capacitor. Though it solved the harmonic magnification problem and improved the PF, it could not solve the repetitive equipment failure and nuisance tripping problem, and the detuned filter itself failed frequently needing continuous component replacement. Besides, it can not reduce harmonics. When the real solution arrives, the detuned filter needs to be replaced, paving the space for the super tuned harmonic filter that solves all the failure and tripping issues besides slashing down harmonics, both THDi and THDv, within IEEE 519 limits.
How did the high harmonics bring in Power Quality Problem and unwanted equipment tripping in the tire industry? Well, that issue explained in details in another webpage "Power Quality Solution Delivered". What did it take to resolve both the trouble, equipment failure and nuisance tripping? The approach to the solution, its methodology and efficacy described exhaustively on another webpage "Passive Harmonic Filter proven valuable When Equipment Fails".
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