An Estimation Method to Determine Equivalent Circuit Parameters for Harmonic Analysis

This paper proposes a new estimation method to determine arbitrary circuit parameters for the harmonic analysis of a distribution network. Harmonic analysis is important in maintaining electric power quality. An interesting phenomenon, a temporary cut-down of the harmonic voltage level at dawn, even if demand is slightly increasing at this time, is often observed in actual power systems. This paper proposes to utilize observations of this phenomenon to estimate circuit parameters. In addition, it is claimed that a detailed equivalent circuit is preferable to a conventional simplified equivalent circuit for explaining the phenomenon. This paper also discusses the usefulness of the Harmonic Characteristics Curve, which is proposed in this paper as a new concept, at the secondary winding of the distribution transformer, and the correlation of PQ, the monitored values of the active and reactive power at the secondary winding of distribution transformer. This correlation should determine the equivalent fundamental frequency admittance of the shunt capacitors installed for distribution lines. (c) 2014 Wiley Periodicals, Inc. Electr Eng Jpn, 187(1): 16-23, 2014; Published online in Wiley Online Library (). DOI 10.1002/eej.22451