High Voltage AC Transmission Lines: Reduction of Corona Under Foul Weather

Mechanism of the tonal emission from ac high voltage overhead transmission lines

“…the crackling noise, originating from the pulse-shaped discharges to be responsible for the 2f -emission. However, this contradicts the observation mentioned above, with 2f -emission being independent of the occurrence of pulse-shaped discharges [3,14,15]. Further, in [17] a modulation of energy pulses, i.e.…”

“…However, as it only contributes a minor share to the A-weighted level, the low-frequency tonal noise went largely unnoticed or uncommented. More detailed observations on the 2f -emission originate from experiments on short conductorsamples [3,14,15]. There is evidence provided that the frequency of the emission is related to the mains frequency by the factor of two, as the emission always occurs at twice the frequency of the voltage even if this latter frequency is changed [15].…”

“…There is evidence provided that the frequency of the emission is related to the mains frequency by the factor of two, as the emission always occurs at twice the frequency of the voltage even if this latter frequency is changed [15]. As the predominant type of corona discharges is changed to glow discharges, adding of metallic protrusions on conductors results in a decrease of the A-weighted overall noise level; however, 2f -levels remain unreduced [3,14,15]. Therefore, the 2f -emission seems to be connected to the occurrence of ac-corona, while it is independent of the occurrence of the type of corona discharges responsible for the hissing and crackling noise component.…”

Experimental verification of the potential of superhydrophobic surfaces in reducing audible noise on HVAC overhead line conductors

“…Surface treatments have previously been applied to conductors to examine their effects on audible noise. Paul [34] compared the noise performance of a hydrophobic conductor condensed with a paraffin film and a hydrophilic conductor prepared by heating it in an oven to 600°C. The results show that the hydrophobic conductor reduces noise level at low electric fields (around 11 kV/cm) and the hydrophilic conductor shows a reduction at 10–15 kV/cm.…”

Modelling of the inhibition effect of thin‐wire ultra‐corona on upward leader and its application on lightning protection in high‐voltage transmission lines

“…The results showed that the application of thin wire affects the corona mode from streamer to glow, suppressing streamer formation effectively. Heroux et al [10] found that the ionic space charges produced by ultra-corona lower the electric field at the conductor surface, tending to suppress corona activity; subsequently, streamers do not develop. However, they did not advise to apply thin wires on transmission power conductors to avoid great corona losses.…”