I'm analyzing interval data for a Westar Energy customer in Wichita and seeing some confusing demand reset patterns. The tariff says demand is measured over consecutive 15-minute intervals, but I'm seeing what looks like 30-minute demand windows in the interval data. Some 15-minute periods show zero demand followed by double the expected reading in the next interval. Is Westar using 30-minute sliding demand measurement? The customer's monthly demand charge jumped from $2,400 to $4,100 and I can't figure out why the demand readings don't match their actual load pattern.
Westar Energy demand reset intervals - am I reading this right?
Bonnie, Westar uses thermal demand metering on some of their older installations. The meter averages load over a sliding 15-minute window but only updates the demand register every 30 minutes or at the end of the billing period, whichever is higher. So you might see zero readings followed by a catch-up reading that covers two intervals. MLGW had similar metering setups before our AMI upgrade. Check if this is an older electromechanical demand meter versus the newer digital AMI meters.
Also, Westar's older GE demand meters sometimes have a thermal reset delay where the demand register doesn't immediately drop to zero after the measurement interval. This can create confusing interval data where demand appears to carry over between measurement periods. Request a meter test to verify the demand measurement accuracy and timing. If it's an older meter, they might need to adjust the billing calculation method.