海拔对直流输电线路可听噪声及其频谱特性影响的试验研究

Experimental Study of the Influence of Altitude on Audible Noise and Its Spectrum Characteristics for DC Transmission Line

为深入研究高海拔地区高压直流输电线路电晕可听噪声的特性规律,基于海拔1700m、3400m和4300m的三处直流模拟试验线段,开展不同电压下的双极直流输电线路可听噪声的海拔影响试验,获得了不同导线表面场强、不同海拔的可听噪声A声级和频谱特性规律。试验研究表明:随着海拔的增加,直流输电线路可听噪声A声级呈非线性变化规律,在较高海拔高度下,增加趋势逐渐趋缓;直流输电线路A声级噪声的能量主要集中在2000~10000Hz的频带范围内,其中2~2.5kHz和5~8kHz范围内的单频噪声声压级的海拔变化规律与总体A声级噪声符合性较好,5~8kHz频带范围的抗背景噪声干扰能力更强;在5~8kHz频带范围内,A声级噪声与单频噪声分量的差值范围约8.0~10.6dB,在环境背景噪声干扰较大时,可通过分析单频噪声声压级获得不同海拔直流输电线路的A声级噪声及其海拔修正规律。

In order to study the characteristics of coronagenerated audible noise(AN) from HVDC lines at high altitude area, based on the three DC reduced-scale test lines at 1700 m, 3400 m and 4300 m elevation, the AN test of bipolar HVDC lines with different voltages was carried out, and the A-weighted sound pressure level(A-SPL) and its spectrum characteristics with different surface field strength and different altitude were obtained. The experimental results show that, with the increase of altitude, the A-SPL of HVDC transmission line presents a non-linear change rule, and the increasing trend gradually slows down at higher altitude. The frequency components of the corona-generated AN from the transmission line at the high altitude area were mainly concentrated in the frequency range of 2000 to 20000 Hz. The altitude correction law of single frequency sound pressure level in the range of 2~2.5 kHz and 5~8 kHz is in good agreement with that of A-SPL, and 5~8 kHz frequency band has stronger anti background interference ability. In the frequency range of 5~8 kHz, the difference between A-SPL and single frequency noise component is about 8.0~10.6 dB. When the background noise is large, the A-SPL of HVDC transmission line and its altitude correction law can be obtained by analyzing the sound pressure level of single frequency.