直流老化导线表面形貌表征及其与可听噪声关联特性的研究

The conductor surface aging and audible noise of long-term operation of HVDC transmission line have become one of the important issues that restrict the development of HVDC transmission lines. In this paper, the surface morphology of the DC aging wire is the research object. The micro-morphology and material composition of the aging conductors have been measured. The roughness parameter system, power spectral density and fractal theory are proposed to analyze the surface morphology characterization, which reveals the rule of aging evolution of surface morphology. A time-frequency and frequency-domain measurement system of audible noise based on DC corona cage and reduced-scale test line is constructed. In the frequency domain, the relationships between the sound pressure level, the spectrum distribution, the spectrum characteristic of corona current, the surface morphology characterization parameters and the power spectrum are studied. In the time domain, the time-domain pulse characteristics of the audible noise of aging conductor, the time-domain waveform characteristics of the corona current and ultraviolet current are researched. The correlations between the fractal dimension of surface morphology and the time-domain wave of acoustic pulse, corona current and ultraviolet current are established. The models of DC corona single source and multiple random noise sources considering space charge distribution are proposed. Revealing the intrinsic relationship between the surface characterization of the conductor and the audible noise helps optimize the design of the DC transmission line structure and the wire selection so that the audible noise level of designed conductor can meet environmental requirements during its service life.

长期运行的高压直流输电线路，导线表面严重老化，其电晕可听噪声问题，已成为制约高压直流输电线路发展的重要因素之一。本文以直流老化导线为研究对象，测量了不同老化程度导线表面的微观形貌及物质成分，提出了采用形貌参数体系、功率谱密度、分形理论来从不同层面对导线表面形貌进行表征, 揭示导线表面老化演变规律。为了深入研究导线表面状态与可听噪声的内在关系，搭建基于直流电晕笼及实验线段的可听噪声时域频域测量系统。在频域内，研究噪声声压级及频谱分布、电晕电流频谱特征与表面形貌参数及功率谱密度的关系。在时域内，研究可听噪声声波脉冲、电晕电流、紫外光电流的时域波形特征，建立导线表面形貌参数、分形维数与声波脉冲、电晕电流及光电流波形参数的关联特性。建立计及空间电荷分布的直流电晕单声源及多个随机噪声源的模型。研究成果有助于优化直流输电线路结构与导线选型设计，从而使设计的导线在使用寿命内，其可听噪声满足环保要求。

随着我国多条高压及特高压直流输电线路的全面建成投入运行，高压直流运行导线的长期运行老化特性及电磁环境成为直流输电线路运行后的重要问题。本课题以直流老化导线为研究对象，通过测量不同老化程度导线表面的微观形貌及物质成分，提出了采用形貌参数体系、功率谱密度、分形理论来从不同层面对导线表面形貌进行表征，揭示了导线表面老化演变规律。通过搭建基于直流实验线段的可听噪声时域频域测量系统。在频域内，研究了噪声声压级及频谱分布、电晕电流频谱特征与表面形貌参数及功率谱密度的关系。在时域内，研究了可听噪声声波脉冲、电晕电流、紫外光电流的时域波形特征，建立了导线表面形貌 参数、分形维数与声波脉冲、电晕电流及光电流波形参数的关联特性。在可听噪声的数值建模方面，建立了计及空间电荷分布的直流电晕单声源及多个随机噪声源的模型。本课题的研究成果有助于优化直流输电线路结构与导线选型设计，从而使设计的导线在使用寿命内，其可听噪声满足环保要求。