Power Analysis and Its Measurement Research under Harmonic Circumstances

Due to the rapid growth of non-linear loads in power systems, harmonic pollution is becoming more and more serious. Begin with the definition of harmonic power, the direction of power flow is analyzed from the sides of both fundamental and harmonic wave. Through a harmonic simulation circuit based on PSCAD/EMTDC, the conclusion that as a result of harmonic, harmonic-sources have their metered electric energy reduced, while non-harmonic-sources increased has been brought out. What's more, according to the result of simulation, the interactive influence of fundamental and harmonic wave on power measurement is proposed. Due to the above conclusion and the work principles of electromagnetic induction meter and electric meter, the reasons of measurement errors are found. And at the end of this paper, the development and current status of power definition which is a necessary key to the power measurement are discussed.