Finally resolved a power factor nightmare with Northeast Utilities (now Eversource) that had been dragging on for over a year. Manufacturing client was getting power factor penalties averaging $12,000/month even after installing capacitor banks. Problem was NU's power factor measurement methodology was calculating reactive power incorrectly during harmonic distortion events. Total recovery $156,000 plus they agreed to use RMS measurement methodology going forward.
Power Factor Penalty Reversal - Northeast Utilities Mess
Vince, that sounds like a highly technical case. How did you identify that harmonics were affecting their power factor calculations? Did you have to bring in power quality experts or were you able to document it yourself?
Jim - I had to hire a power quality consultant with specialized harmonic measurement equipment. The client's plant had significant harmonic distortion from variable frequency drives that was causing NU's meters to calculate incorrect power factor during certain operating conditions. The consultant's $8,500 report was worth every penny to prove the measurement methodology was flawed.
Vince, I've seen similar issues here in Ohio with FirstEnergy where harmonics mess up power factor measurements. What was Northeast Utilities' initial response when you presented the harmonic analysis? Did they acknowledge the measurement problem right away?
Frank - initially NU claimed their meters were accurate and the customer needed better power factor correction equipment. It took three rounds of technical meetings and finally a demonstration with portable power quality analyzers to convince them their measurement methodology was the problem. Utilities hate admitting their metering is wrong.
Vince, did this affect other customers with similar harmonic issues or was it isolated to your client? Seems like NU might have had systemic power factor measurement problems if harmonics were causing calculation errors.
Derek - great question. During settlement discussions NU admitted they had "similar concerns" with other industrial accounts but wouldn't give specifics. I suspect this was a widespread issue but they weren't about to open that can of worms. The settlement included confidentiality provisions that prevented me from publicizing the measurement methodology problems.
Vince, the confidentiality clause is unfortunate because other customers probably had the same problem. Here in Pittsburgh I've suspected Duquesne Light has similar harmonic-related power factor calculation issues but haven't had the budget for power quality analysis. Your case gives me ammunition to pursue it further.
Walt - if you pursue it, make sure your power quality consultant is familiar with IEEE 519 harmonic standards and can explain how harmonics affect different power factor calculation methods. The key is showing that RMS measurement is more accurate than the utility's standard methodology when harmonics are present.
Vince, what type of manufacturing was your client doing that created so much harmonic distortion? I'm dealing with a data center here in Atlanta that has similar power factor penalty issues and wondering if harmonics could be the culprit.
Rachel - automotive parts manufacturing with lots of CNC machines and variable speed drives. Data centers definitely create harmonic distortion from all the switching power supplies and UPS systems. Worth investigating if your client has power factor penalties that don't make sense given their installed correction equipment.
This is fascinating technical discussion. Here in Nevada with NV Energy we don't see as many power factor issues, but I'm starting to think I should be looking more carefully at harmonic distortion effects. Vince, do you have recommendations for affordable power quality analysis equipment?
Kim - for basic harmonic analysis I've had good results with Fluke power quality analyzers, but for detailed power factor methodology disputes you really need a consultant with more sophisticated equipment. The rental costs for high-end analyzers usually justify hiring an expert rather than buying equipment.
Vince, excellent case study on the intersection of power quality and billing accuracy. This is exactly the kind of technical expertise that sets professional auditors apart. The harmonic distortion angle on power factor penalties is something more auditors need to understand. Great work getting that $156K recovery!