Demand calculation methods

Power demand is the energy accumulated during a specified period divided by the length of the period. Current demand is calculated using arithmetical integration of the current RMS values during a time period, divided by the length of the period. How the meter performs this calculation depends on the selected method. To be compatible with electric utility billing practices, the meter provides the block interval power/current demand calculations.

For block interval demand calculations, you select a block of time (interval) that the meter uses for the demand calculation and the mode the meter uses to handle the interval. 2 different modes are possible:

• Fixed block - Select an interval from 1 to 60 minutes (in 1 minute increments). The meter calculates and updates the demand at the end of each interval.

• Sliding block - Select an interval from the range 10, 15, 20, 30, 60 minutes. For demand intervals less than 15 minutes, the value is updated every 15 seconds. For demand intervals of 15 minutes and greater, the demand value is updated every 60 seconds. The meter displays the demand value for the last completed interval.

The following figures illustrate the 2 ways to calculate demand power using the block method. For illustration purposes, the interval is set to 15 minutes.