
Economic Use of Power 277
Example 11.5
A daily power consumption profile of a customer is shown in the table below,
where the kW loads are average over the period listed and kVA demand meter
readings are peak over 15 min intervals during the period. This pattern repeats for
all days in a 30-day month. The utility tariff to this consumer is 12 cents per kWh
plus $15 per peak kVA demand over the month. Determine the monthly utility bill
(a) with present usage pattern, and (b) with pf improved to unity. Also determine
the daily load factor of this consumer as seen by the utility company.
Time Period Power Usage kW kVA Demand
12 a.m.–4 a.m. 100