Statistical Measurements and Modelling of HVDC Powerline Noise

Both basic and statistical measurements of the HF radio noise environment near a HVDC transmission line and converter station were made in Winnipeg in July 1977. Values of Vrms and Vd were calculated from the amplitude probability distributions (APD) of the radio noise and were found to compare favourably with the directly measured values. Four models, the Rayleigh and three others, which were designed for atmospheric noise, were fitted to the measured APD data. All four models used values of Vrms and Vd as input parameters. Because of the location and nature of the source, the noise was inherently non-Gaussian, thus, the Rayleigh model was a poor fit. The Atmospheric, Log-Normal and Hall (8=3) models gave accurate predictions of the measured APDs. The average crossing rate (ACR) characteristics from the Log-Normal and Hall (8=3) models again using Vrms and Vd values as inputs also compared favourably with the measured ACR data. This paper demonstrates that mathematical models designed originally for atmospheric radio noise may be used to characterize at least certain types of man-made noise.