Reactive Power Billing Under Nonsinusoidal Conditions for Low-Voltage Systems

This paper analyzes reactive power definitions for billing purposes in low-voltage installations with high harmonic distortion levels. First, the theoretical definitions of power under nonsinusoidal conditions and their outcomes are presented and two of them are chosen as the focus to determine which one is the most appropriate for billing: nonactive power and fundamental reactive power. The regulatory framework of different countries is then analyzed and compared with the theoretical definitions. Subsequently, different reactive power measurement methods are analyzed and their outputs are again compared with the definitions. Simulations performed with typical nonsinusoidal voltage and current signals show that several measurement techniques can easily be used for fundamental reactive power measurement, whereas the measurement of nonactive power requires more effort. Finally, a regulatory comparison of the pros and cons of each reactive power quantity is conducted. It is concluded that the surplus of reactive power in electricity grids should be controlled via fundamental reactive power (or displacement power factor), since it is independent of the harmonic distortion, the responsibility for it can be easily assigned, and it is easy to be measured with the use of several simple electronic measurement techniques.