Working on a PPL Electric case here in Harrisburg and their TOU-Large schedule definitions are confusing me. Tariff says peak hours are 8am-8pm Monday-Friday excluding holidays but the interval billing shows charges during what should be off-peak windows. Client has consistent load profile - medical facility that draws 400-500 kW pretty evenly throughout business hours. Seeing peak demand charges applied at 7:30am and 8:15pm which should be outside the window. Am I missing something about how PPL defines their TOU periods?
PPL TOU Schedule analysis - peak period definitions seem inconsistent
Sylvia, check if PPL uses ending interval method vs beginning interval. Down here with Alabama Power we learned that 8:00am peak start means intervals ending at 8:00am are still off-peak, but intervals ending at 8:15am are peak. Your 7:30am charge might be for 7:45am ending interval if they read every 15 minutes. Also verify their holiday schedule - utilities define holidays differently and that affects TOU applications. Medical facilities usually have good documentation so cross-reference their actual usage timing with the interval data.
Albert's got it right about interval ending times. IPL uses same method here in Indiana. The 8:15pm charge Sylvia mentioned definitely sounds like billing error though - that's 15 minutes past the 8pm cutoff even with ending interval logic. PPL has had issues with their TOU billing system since they upgraded in 2013. I'd request detailed interval exports for the disputed months and compare against their published TOU schedule. Medical facilities are great clients for this analysis because their load patterns are so predictable.
Had similar confusion with Duke Energy Ohio TOU schedules last month. Their peak window definitions changed slightly when they merged Cincinnati Gas & Electric systems. What solved it was getting PPL's actual billing determinant report - not just the summary bill but the detailed interval breakdown showing which 15-minute periods were classified as peak vs off-peak. That report will show exactly how they're interpreting the 8am-8pm window. If there are errors the pattern should be obvious when you map it against the tariff language.