VOLTAGE SAGS PROFILE ESTIMATION FOR POWER DISTRIBUTION SYSTEMS

In recent years, the need to characterize the feeder-level power quality performance has emerged. This is driven by the interest to compare the PQ performance among utility companies or among various feeders. Since it is impossible to measure the sag level at every node of a distribution feeder, estimation of sag characteristics at un-metered nodes becomes necessary. For meeting the need, The concept of voltage sags profile estimation and the practical method based on a least-square algorithm are proposed to deal with this problem. The proposed method achieves the sags profile estimation with fault phase judging and fault path searching. One of the potential applications of the proposed method is to calculate the feeder power quality performance indices such as System Average RMS Frequency Index (SARFIx).