Both ANSI C84.1 and our rules warn the customer that deviations will occur but we have no current means to forecast their occurrence nor do we maintain a complete history of their occurrence. This lack of forecasting or history makes it extremely difficult to make economic decisions regarding mitigation measures. Electric Power Electrical power in an AC circuit has three components. Real power is considered to be the work-producing component. Reactive power is not used to do work but is needed within an electrical system to operate equipment such as motors and transformers.
Apparent power comprises both real and reactive power and is measured in units of volt-amperes.
Textbooks and common use refer to watts as real power which is, in fact, misleading for two reasons. First, all electrical equipment is rated in apparent power, voltamps because it must handle the full RMS current. It is an error to assume that reactive or harmonic currents should not be of concern. The ratio of real power consumed to apparent power is the power factor. True power factor includes all frequencies, not just 60Hz.