Evaluation of the Measures to Limit the Corona Noise Implemented on the 400 kV OTL Bericevo – Krsko

On 18 November 2013 a new 80 km long 400 kV double-circuit OTL Bericevo – Krško fitted with horizontal twin-bundle conductors (conductor 490 AL1/64 A20SA, 400 mm spacing) was put in operation. The hydrophilic conductors, manufactured by glass pearl blasting technology, were installed in two sections. Both sections were selected to serve as a test site for the OTL audible noise investigation based on proven measurements. The purpose of this investigation was to properly assess the improvement, which was mainly audible noise reduction, expected by the usage of hydrophilic conductors, and to gain insight into the correlation between atmospheric conditions (air pressure, temperature, humidity, rain etc.), corona and the audible noise produced by corona. The audible noise measurements were…