Got a weird situation at a GM plant in Ohio. DTE is billing them for neutral current on their primary meter, claiming severe three-phase imbalance. The plant electrician swears everything is balanced, but the bills show $3,200/month in imbalance charges. Anyone dealt with this before?
Three-Phase Load Imbalance at Auto Assembly Plant
Omar, I've seen this with large motor loads that cycle on and off frequently. The billing demand might be capturing peak imbalance moments even if the average looks balanced. Do they have any large single-phase loads or DC rectifiers?
Albert's right about the cycling loads. Auto plants often have welding equipment and large motors that create transient imbalances. The utility meter might be more sensitive than the plant's monitoring equipment. I'd suggest installing a power quality meter for a month to capture the real-time data.
Good point about the welding equipment - they do run a lot of robotic welders on one phase. I'll recommend they install monitoring and maybe look into load balancing solutions. Those imbalance charges really add up over time.
This is a great example of why industrial audits need to go beyond just rate analysis. Equipment issues can create billing problems that aren't obvious from just looking at the tariff. Keep us posted on what the monitoring shows.