Got a steel foundry in Indiana on Duke Energy that's getting hammered with power factor penalties. They're running around 0.78 power factor and Duke charges penalties below 0.85. The monthly penalty is running $4,200-$5,800. Plant has a lot of induction furnaces and old motors. What's the most cost-effective approach for power factor correction in a foundry environment?
Power factor penalties hitting steel foundry hard
Iris, steel foundries are tough because of all the arc furnace harmonics. Standard capacitor banks often don't work well. We had success with a foundry in Gary using harmonic filters combined with capacitors. Initial cost was $180K but they're saving $4,500/month in penalties plus some energy savings.
Arnold, that's a good payback period. Did they have issues with capacitor switching causing voltage flicker? This plant is worried about affecting their precision grinding operations.
They used automatic switched capacitor banks with slow switching contactors to minimize transients. The harmonic filters actually helped stabilize voltage quality. No issues with the grinding ops after installation.
Another option is to look at upgrading some of those old motors to high-efficiency models with better power factor. We replaced 8 motors at a foundry in Ohio and improved their overall PF from 0.76 to 0.82 just from the motor upgrades.