Measurements and modelling of the HF radio noise environment near an HVDC converter station

Measurements of the HF radio noise environment near an HVDC transmission line and converter station were made outside Winnipeg in July 1977. Typical levels and characteristics are presented for various combinations of mercury arc valve noise, AC hum and DC corona from a number of sites within eight kilometers of the converter station. In addition, two sets of measurements were taken 80 km from the converter station. Values of the root-mean-square, average and quasipeak voltages were calculated from the Amplitude Probability Distribution (APDs) of the noise and were found to compare favorably with the directly measured values. Four mathematical models, the Rayleigh and three others which were developed for atmospheric noise were fitted to the measured APD data. Using inputs of v sub rms and V sub d the Log-Normal model produced the most accurate predictions of the measured APDs. The Log-Normal and the Hall models both fitted the measured Average Crossing Rate data equally well.