A method for real-time, wide-band identification of the source impedance in power systems

In this paper, the principal problems of distribution system identification and accurate measurements of distribution system impedance frequency contour are discussed. Some new results of field identification are presented. The focus of this paper is on the effective method of signal processing adapted to real signals which appear in the power systems. The principal problem of accurate identification is in the system nonstationariness. Its influence on accuracy is discussed and illustrated with experimental results. The proposed method of impedance identification based on short 40-ms system observations is relatively insensitive to power system nonstationariness. The presented discussion confirms that, with the proper signal processing, 1-s-long system observations are quite sufficient to describe the system with an accuracy to satisfy practical demands.