Examination of Grizzly Mountain database to determine effects of relative air density and conductor temperature on HVDC corona phenomena

A summary is presented of the results of an effort to determine the effect of relative air density (RAD) and conductor temperature on HVDC (high-voltage direct current) corona phenomena by statistically examining fair weather audible noise (AN), radio noise (RI), ion-enhanced electric field, and ion current density data in the 1986 database from the Grizzly Mountain HVDC Research Project. Since wind has such a strong effect on DC electric fields and ions, this comparison was made under the calm wind conditions of speeds less than 1 m/s. The results of this effort demonstrated that AN, RI, negative electric field, and negative ion current density increase with increasing ambient and conductor temperature and decrease with increasing RAD. However, positive electric fields and positive ion current densities showed essentially no correlation with either conductor temperature or RAD