Electric energy measurement based on the effective absorbed power under non-sinusoidal conditions

Abstract

Along with the rapid development of power electronic technology, the application of non-liner load becomes more and more with the capacity becomes larger and larger. Massive harmonics are poured into the power grid, leading to the distortion of the system voltage and current. Meanwhile, the nonliner loads usually own complex characteristics such as power inrushing, three phase imbalance, harmonics, inter-harmonics, and so on, which directly affect the correctness and validity of energy measuring. Therefore, the energy metering instrument which designs based on the sine power theory or the traditional non-sinusoidal power theory can not reflect the real energy that the loads absorb form the system. The correct definition and measurement of power under distortion condition become a matter of common concern both to the power supply system and the customers. In this paper, IEEE Std. 1459-2000 is studied and a novel energy measuring method based on the effective absorbed power is put forward. Beginning with the analysis of energy transmission and the line-loss, the total energy of the system is quantified. The shortcomings of the traditional power theory and the corresponding algorithm in analyzing the energy measurement are studied comprehensively. In view of the background harmonic, the energy measuring methods are studied from the line-loss and effective absorbed power. The analysis results indicate that the method proposed in this paper can correctly reflect the power consumption of the surge loads and the exchange energy.