为准确地在户外进行特高压直流输电线路的可听噪声测量,以及研究可听噪声与电晕放电的关联特性,利用国家电网公司特高压直流试验基地的电晕笼,对直流线路的电晕噪声和几种典型背景噪声的频谱进行了测量和分析:对比了电晕笼内正极直流线路电晕噪声和背景噪声的频谱特性差异;同时给出了不同导线表面电场强度对正极电晕噪声频谱的差异;分析了电晕噪声A声级与其各频谱分量差值的稳定性。得出了与背景噪声区别较大、稳定性较好的电晕噪声频段,并最终得到了在电晕笼内测量得到的电晕噪声A声级与其8kHz分量之差为11dB的数值关系。在电晕笼内开展的4×1 000mm2导线可听噪声试验证实了该方法的有效性。
In order to measure audible noise of UHVDC transmission lines in outdoors accurately, and to study the relation between corona discharge and the audible noise, using a corona cage in UHVDC Test Base of State Grid Corporation, we experimentally measured and analyzed corona noise and some different typical background noise spectra of DC lines. The difference between spectrum characteristics of positive corona noise and background noise was studied firstly, as well as the difference in spectrum characteristics of positive corona noises aroused by different conduct surface electric fields. Then, stability of relations between A sound level and its spectral components of corona noise was analyzed. A stable corona noise band differing largely from background noises was obtained, and a numerical difference of 11dB between the corona noise's A sound level and 8 kHz audible noise band component which were measured in the corona cage was obtained. An audible noise test of 4 × 1000 mm2 conductor in the corona cage confirmed the validity of the proposed method.