Working with an automotive assembly plant in Michigan - DTE territory. They're getting hammered with power factor penalties averaging $8,500/month. Current PF is running around 0.78-0.82 lagging. Plant manager is asking about capacitor banks vs synchronous condensers. Anyone have experience with PF correction in auto manufacturing? These guys have massive induction motor loads from the assembly line equipment.
Power Factor Penalties - Auto Assembly Plant
Gloria - Auto plants are tough because of all the variable frequency drives and welding equipment. Capacitor banks are usually the most cost-effective solution, but you need to be careful about harmonics. Had a similar client install 2.4 MVAR of capacitors and got their PF up to 0.95. Paid for itself in 14 months. What's DTE's penalty threshold?
DTE starts penalizing below 0.85 PF. George, did your client have harmonic issues with the capacitors? I'm worried about resonance problems with all the VFDs they're running. Plant has about 40 large drives for conveyor systems and robotic equipment.
We did a harmonic analysis first and ended up using detuned capacitor banks with 5th and 7th harmonic reactors. Little more expensive upfront but avoided any resonance issues. Definitely recommend getting a power quality study done before installing anything. The VFDs can create some nasty interactions.
Another option is active power factor correction - more expensive but handles the harmonics better with VFD loads. Had a pharma plant go that route and got PF up to 0.98 with cleaner power quality overall. Might be worth considering for a facility that complex.