Carl N. in Denver. Three-phase customer with one dead phase for 6 weeks before Xcel found it. Demand readings were showing 60% of actual because two phases measured normally but third phase CT wasn't registering. Energy consumption looked right but demand charges way low on Schedule TOU-GSD-A. Xcel wants to back-calculate demand using power factor assumptions. This seem right to everyone?
Dead Phase Causing Demand Multiplier Issues
Randy Dawson here. Carl, dead phase situations are tricky for demand reconstruction. The utility should use actual load data from the working phases and apply diversity factors based on your specific equipment, not just generic power factor assumptions. Request they provide their calculation methodology in writing and compare against any sub-metering data you might have. If it's a large adjustment, consider hiring an engineer to validate their reconstruction method.
Pete T. from San Jose. PG&E did similar reconstruction on a data center with failed PT. They used 15-minute interval data from good phases and applied load balance algorithms. Came within 3% of our internal metering. Key is making sure they account for your actual equipment characteristics not just textbook formulas.
Lloyd F. in Augusta GA. Georgia Power handles these as equipment failure adjustments. They typically use thermal demand analysis if the failure period is long enough. For 6 weeks you should have good baseline data from before and after to validate their calculations.
Lou W. from El Paso. El Paso Electric uses kW/kVA ratios from adjacent billing periods to reconstruct missing demand data. Usually pretty accurate for consistent loads. Make sure they don't penalize you with assumed poor power factor if your actual PF is better than their assumption.
Carl N. update. Xcel agreed to use our backup metering data to validate their reconstruction. Turns out their power factor assumption was too conservative. Final adjustment about 15% higher than their initial calculation but still reasonable compared to normal billing periods. Good outcome overall.
Art K. also in Denver. Had dead phase issue with Xcel couple years back. They were pretty reasonable once you get past first-level customer service. Their engineering group knows how to handle these properly. Glad it worked out Carl.
Bob O. from Fayetteville AR. Entergy Arkansas uses similar reconstruction methods. Usually works out fair if you stay engaged in the process. Don't just accept their first calculation without asking questions about the methodology.