Audible noise spectral characteristics of high‐voltage ac bundled conductors at high altitude

Abstract

At high altitudes, the corona discharge around a conductor surface is severe, and the induced audible noise (AN) is irritating; this is due to the low air density at high altitudes. Therefore, AN has become a crucial limiting factor in the design of ac power lines of 500 kV or higher at high altitudes. An investigation of the spectral characteristics of AN should help provide a greater understanding of corona noise; however, only a few studies have investigated the spectral characteristics of AN in practical bundled conductors at high altitude. Therefore, it is difficult for power utility companies to select suitable conductors. In this study, the AN spectral characteristics of 6 × LGJ400, 6 × LGJ720, and 8 × LGJ500 bundled conductors were investigated using an ultra‐high‐voltage corona cage (8 × 8 × 35 m) in Xining, Qinghai Province (altitude: 2261 m). The AN equivalent A‐weighted level and the 1/3‐octave frequency characteristics of these three conductors were obtained, and the influence of the electric field (E‐field) on these characteristics was analysed. Subsequently, the relationship between the AN A‐weighted level and the 8‐kHz level was examined. We found that, with the increase of the E‐field, the low‐frequency components of AN level did not exhibit an obvious trend, but in the high‐frequency band (1.6–20 kHz), a clear positive correlation was observed between the spectrum level and E‐field strength. Among these three conductors, the 8 × LGJ500 conductor was the optimal conductor for reducing the AN levels at high altitude. The results obtained in this study can provide a data reference for the construction of high‐altitude ac power lines.

Corona current and audible noise characteristics of HVDC transmission lines and their relationship at high‐altitude

“…With the altitude increases, the air density decreases, the electron free travel increases, so does the kinetic energy accumulated by the electrons in a free travel, and the probability of ionization after the electrons collide with air molecules, which leads to a higher occurrence probability of corona discharge on the conductor surface [2]. Corona discharge will not only waste electrical energy, but also produce corona current pulses to squeeze the air around the conductor, cause local air pressure changes, and create audible noise (AN) distinguishable to human ears [3]. When the transmission line voltage and transmission line structure are the same, the AN caused by corona discharge of HVDC transmission lines in high-altitude areas is more intense than that in low-altitude areas, making itself an important issue to be considered when constructing HVDC transmission lines in high-altitude areas.…”

DC negative corona discharge characteristics of the needle-plate electrode under different air pressures

“…However, in the course of the line design, some DC transmission lines will unavoidably cross high-altitude regions. The lower atmospheric pressure is more likely to produce the corona discharge phenomenon and carry with them issues with the electromagnetic surroundings like audible noise, radio interference, and corona loss [1][2][3][4] .…”

Characteristics analysis of positive DC corona audible noise of copper wire with different diameter in high altitude

“…In order to explore the problem of audible noise in high altitude areas, different countries and scholars have built corona cage test devices or carried out long-term measurement of actual lines in high altitude areas. The corona discharge audible noise data [6][7][8] of AC and DC transmission lines in high altitude areas under different weather conditions were measured. It provides a lot of valuable research for the electromagnetic environment problems of rainfall, icing and low pressure environment in the high altitude area of about 2000m.…”