I've got a complex situation with PECO here in Philadelphia. Data center client is getting hit with power factor penalties despite having power factor correction equipment that should maintain 0.95+ PF. The issue appears to be harmonic distortion from the UPS systems and server loads affecting the meter's PF calculations. PECO is measuring displacement power factor but the penalties are based on true power factor. Has anyone successfully disputed PF penalties based on harmonic measurement issues?
PECO power factor dispute - harmonics affecting measurement
Phil, that's a tricky situation. We've seen similar issues with Duquesne Light and data centers. The key is understanding exactly what the tariff specifies - displacement PF vs true PF. If PECO's tariff language is ambiguous, you might have grounds for dispute based on the measurement methodology.
Phil, SMUD here in Sacramento dealt with this issue a few years ago. They ended up clarifying their tariff to specify true power factor for customers with significant harmonic content. The dispute process was lengthy but they credited about 60% of the penalties once they acknowledged the measurement confusion.
Jennifer, that's encouraging. I've pulled PECO's tariff and the language just says "power factor" without specifying displacement vs true. The penalties are substantial - about $8,000/month for the past 6 months. Did SMUD require any specific harmonic analysis or measurement data for the dispute?
Yes, we had to provide a detailed harmonic analysis showing the distortion levels and demonstrating that the displacement PF was actually above 0.95. Cost about $3,000 for the power quality study but well worth it given the monthly penalties. The key was showing the fundamental frequency PF met their requirements.
Phil, make sure you document the UPS specifications too. Many modern UPS systems are designed to maintain good displacement PF but the switching frequency creates harmonics that affect true PF measurements. The manufacturer specs might support your case that the equipment is performing as designed.
Good point Bonnie. The UPS systems are rated for 0.99 displacement PF but the harmonic content is significant. I've contacted the manufacturer for detailed power quality specifications. Also scheduling the harmonic analysis Jennifer mentioned - this could be a substantial recovery if successful.
Phil, FirstEnergy up here in Akron has similar issues with data centers. One thing to check is whether PECO's meters are even capable of accurate harmonic measurement. Some older revenue meters give erratic readings with high harmonic content, which might actually support your dispute.
Lloyd, that's an excellent point. I'll research the meter model PECO is using and its harmonic measurement capabilities. The installation is about 5 years old so it might be an older electromechanical meter that isn't designed for modern electronic loads.
Phil, we had a similar case in Dallas with TXU a few years back. Turned out the revenue meter was a 1990s vintage that couldn't handle the harmonic content from VFDs. Once we proved the meter limitations, they agreed to install a modern digital meter and credited 8 months of penalties.
Marcus, that gives me hope. The power quality study came back showing 12% THD with good fundamental PF of 0.97. PECO's meter is indeed an older model from 2004. I'm preparing a formal dispute citing both the tariff ambiguity and meter limitations for harmonic-rich loads.
Phil, sounds like you've built a strong case. 12% THD is significant enough to throw off older meters. When you file the dispute, make sure to request a meter upgrade as part of the resolution. Modern digital meters handle harmonics much better and will prevent future issues.
Update: Filed the dispute three weeks ago and PECO has agreed to review the case. They're sending an engineer to verify our power quality measurements and evaluate the meter performance. Cautiously optimistic but the process is moving forward.
Excellent progress Phil! The fact that they're sending an engineer suggests they're taking the technical issues seriously. Keep us posted on the outcome - this could be valuable precedent for other data center PF disputes.