Investigation on Harmonic Status of Low-voltage Distribution Network and Analysis of Harmonic on Electric Energy Metering

摘要

It is accepted widely that the energy account based on the value of the integral of the active power of only fundamental harmonic, rather than on the integral of the whole active power should be used. And electric energy metering on harmonic in low-voltage network is usually ignored. A closer examination of the method and the investigation of nonlinear customer however, reveal that it is unable to fulfill the task of energy account. In this paper, problems associated with the method are investigated using case studies and mathematical analysis. Furthermore, many data are collected which provide information about the responsibility for harmonic active power losses in the given distribution system. At the same time, this paper proposes a new method to determine the energy account and new power factor is defined. It is considerate that the harmonic distortion power should be accounted while measuring the active power (P) and reactive power (Q). The new power factor definition can reflect the nonlinear load characteristics. Then, nonlinear customers will be charged for their harmonic. The power quality can be improved accordingly.