Minnesota Power just upgraded our customer from mechanical meter to AMI on a 800kW load. Old meter with 400:1 CTs was reading fine for years. New Itron meter programmed with same 400:1 multiplier but usage dropped by half overnight. Customer's process hasn't changed and power factor is normal around 0.92. Minnesota Power insists programming is correct but numbers don't make sense. Anyone dealt with Itron AMI programming issues? Clifford H.
AMI Programming Error After Meter Change - Need Advice
Clifford, this sounds like a CT secondary issue. Some older installations used 5A secondary CTs while newer AMI meters expect 1A secondary. If the CTs weren't changed but meter expects different secondary current, you'll get exactly this kind of error. Check the CT nameplate for secondary rating and verify meter programming matches. Also possible the new meter has different internal scaling factors. Randy D.
Had identical issue with Idaho Power last year. Itron meter was programmed for 1A secondary but CTs were 5A secondary. Meter was reading 1/5 of actual consumption. Idaho Power fixed it remotely once we proved the CT specs. Get them to verify both CT secondary current and meter programming match exactly. Pete M.
You guys were right about the CT secondary issue. Old CTs are 400:5 (5A secondary) but AMI meter was programmed for 1A secondary. Minnesota Power is sending tech out next week to either change CTs to 1A secondary or reprogram meter correctly. Customer's November bill will be estimated. Clifford H.
Clifford what was the final resolution? Duke Energy here in Charlotte has been doing lots of AMI upgrades and I want to know what to watch for. Did they change the CTs or just reprogram the meter? Karen W.
Karen they decided to reprogram the meter for 5A secondary rather than change the CTs. Apparently changing CTs would have required a longer outage and more paperwork. Meter is reading correctly now and they credited the customer for the undercharge in December. Always verify CT secondary current matches meter programming! Clifford H.