Methods for electric power measurements

With the advent of electronic meters, a variety of methods are now practical for measuring electrical quantities such as watts, power factor, VA and VARs, which previously were not possible. However, different methods for measuring these quantities may produce different results under certain conditions. This can be of concern since these quantities may be used for billing or tariff purposes, and there may be a question of what is the most equitable approach for the consumer base and existing rates. These concerns must be weighed against the various metering approaches that can help encourage or discourage specific consumer behavior.