ComEd upgraded our client's transformer from 750kVA to 1500kVA and changed the CTs from 1000:5 to 2000:5. The physical installation looks correct but I think they forgot to update the AMI programming. Bills dropped from $22K to $11K monthly on Rate 6L which makes no sense given increased production. Anyone know ComEd's process for verifying AMI multiplier updates after equipment changes? - Priya N.
AMI Meter Programming Error After Transformer Upgrade
In Alabama we see this all the time with Alabama Power AMI systems. The field crews update the hardware but don't always communicate the changes to the metering department who handles the software. I'd call ComEd's commercial services and ask them to verify the "meter constant" in their system matches the new CT ratio. - Val M.
Priya, check if they're reading the meter locally vs. through AMI. Sometimes during transitions they switch to manual reads with the wrong multiplier. FirstEnergy did this to us in Akron - took six months to sort out because nobody knew if the readings were AMI or manual. - Jim W.
NPPD has a form called "Meter Data Verification Request" for exactly this situation. ComEd probably has something similar. The key is getting them to print out both the physical meter configuration and the billing system configuration to compare. Don't let them just say "it looks right." - Karl D.
This is a classic commissioning gap. The work order shows transformer and CT upgrade but the metering database wasn't updated. Document the timeline of when work was completed vs. when bills changed. ComEd needs to adjust billing back to the upgrade date, not just going forward. Illinois Commerce Commission Rule 280.90 covers meter accuracy disputes. File a formal complaint if they resist - this is their error, not yours. - Randy D.
Had similar issue with Dominion Energy here in Virginia. They upgraded CTs but billing system still had old multiplier for four months. $180K true-up bill nearly killed our client's cash flow. Now I always request written confirmation that billing parameters match physical installation before any major electrical work. - Alice D.
Check the demand readings too. If your peak demand dropped by exactly half when the CTs were doubled, that confirms the programming error. Evergy did this to a client in Wichita - demand went from 800kW to 400kW overnight with no operational changes. - Bonnie F.
Any resolution on this? I have a similar situation brewing with Duquesne Light in Pittsburgh. They're claiming the AMI system automatically updates when CTs are changed but the math doesn't add up. - Frank M.
Frank, yes - took three months but ComEd finally admitted the AMI programming was never updated. Got a $67,000 credit and they implemented a checklist to prevent future occurrences. Keep pushing, these errors are more common than utilities admit. - Priya N.