Strange situation here in Eugene. Client has a metal fabrication shop with a 300kVar capacitor bank that partially failed - looks like 2 of the 6 capacitor units are dead. Now they're getting "leading power factor" penalties from Eugene Water & Electric Board. Never seen this before. Their PF went from 0.92 lagging to 0.85 leading during light load periods. EWEB is charging them a penalty for leading PF under 0.90, claiming it causes voltage regulation problems. Is this normal? The penalty is $850/month on a 280kW service.
Capacitor bank failure causing reverse power factor penalties?
Dave, that's definitely not normal for most utilities, but some do penalize leading power factor. Puget Sound Energy has a similar clause but rarely enforces it. The issue is that leading PF can cause voltage rise on the distribution system, especially during light load periods. Your client probably needs to either repair the cap bank or install automatic switching to disconnect caps when load drops. What's their load profile look like - pretty variable?
I've seen this with Kentucky Utilities when customers over-correct with fixed capacitors. The fab shop probably has highly variable loads - when the big welders and plasma cutters cycle off, the remaining load can't absorb all the reactive power from the caps. Leading PF penalties are rare but utilities use them to prevent customers from becoming "reactive power generators" on their system. You need caps that switch based on actual kVar flow, not just time-of-day.
Load is extremely variable - they run three 150kW plasma tables that cycle on/off throughout the day, plus welding stations. During break periods, the base load drops to maybe 50kW but the caps are still putting out reactive power. Sounds like we need automatic kVar-based switching instead of the current manual setup. Any recommendations for cap bank controllers that work well with this type of load?
For highly variable loads like plasma cutting, look into ABB's RVC series or Schneider's VarSet controllers. They monitor actual kVar flow and can switch cap steps in/out in about 30 seconds. Key is to set the target PF around 0.92-0.95 lagging, not unity. That gives you buffer against going leading during light load periods. Also consider splitting your 300kVar into smaller steps - maybe 6 × 50kVar instead of 2 × 150kVar for better resolution.
Pete's advice is solid. Also check EWEB's tariff carefully - some utilities give you a grace period or minimum threshold before leading PF penalties kick in. Dominion here in Virginia only penalizes if you're leading by more than 0.05 for consecutive months. Might be worth negotiating with EWEB while you're installing the new controller, especially if this is a first-time occurrence due to equipment failure.
Had a similar issue with PPL here in Pennsylvania. Customer was getting leading PF penalties after their building automation system started cycling HVAC loads differently. The key was convincing PPL that it was an unintentional equipment issue, not deliberate over-correction. They waived two months of penalties while we installed proper kVar-responsive switching. Document everything about the capacitor failure - utilities are more forgiving when they see it's a maintenance issue, not poor design.
Good news - EWEB agreed to waive the July penalty after I sent them documentation of the capacitor failure and our repair plan. Installing a new ABB RVC controller with 6-step switching next week. Thanks everyone for the advice. Never thought I'd see a leading power factor penalty in 15 years of doing this work!
Dave, great outcome! For future reference, most utilities with leading PF penalties have them buried deep in their general terms and conditions rather than the rate schedules. Worth checking even if you don't see PF penalties mentioned in the main tariff. Dominion's leading PF clause is in Section 7.3 of their Terms and Conditions, not the actual rate schedules.
This thread is gold - I'm saving it for reference. Tampa Electric has a similar leading PF clause that nobody knows about. Had a client with solar and caps who went leading during sunny low-load periods. TECO hit them with penalties for six months before we figured out what was happening. The interaction between solar production, capacitors, and variable loads creates all kinds of PF scenarios that traditional rules don't cover well.
Kevin raises an excellent point about solar interactions. We're seeing more leading PF issues as customers add solar to facilities that already have power factor correction. The solar inverters can provide reactive power support, but if they're not coordinated with existing cap banks, you can end up over-corrected during peak solar production. Modern inverters have PF control capabilities that need to be integrated with the overall reactive power strategy.