On-line measurement of equivalent parameters of distribution system and its load for harmonic frequencies

An on-line measurement of equivalent parameters of a distribution system and a harmonic generating load is discussed in the paper. Four parameters are the subjects of the measurement: the distribution system and the load complex impedances, the complex rms (crms) values J_n of the load generated current j harmonics and the crms values E _n of the distribution system internal voltage e harmonics. The method discussed is based on measurements performed in two states of the system, before and after disturbing it by a capacitor or by a harmonic generating device. The effects of the random and systematic measurement errors on the calculation accuracy are discussed in the paper. The results are illustrated with computer modeling and with physical measurements