基于紫外差分吸收光谱法的SF_6分解组分CS_2定量检测

Quantitative Detection of the CS_2 Produced by SF_6 Decomposition Based on Ultraviolet Differential Optical Absorption Spectrometry

SF_6作为电气绝缘设备中最常用的绝缘气体,对它的分解组分的检测与研究是相关设备故障诊断和在线监测的重要内容。CS_2作为一种常见的固体绝缘缺陷下的SF_6特征分解产物,在紫外190~210nm波段具有很强的吸收特性。基于紫外差分吸收光谱技术,搭建针对CS_2的紫外光谱检测平台。首先通过实验获得不同浓度CS_2的紫外吸收光谱,再利用基线扣除、小波处理等手段提取吸收光谱中的有效信号,消除了光谱中的高低频噪声,通过快速傅里叶变换(FFT)将光谱信息转换到频域,建立气体浓度与光谱频域特征值之间的线性关系。研究表明,该方法对CS_2检测重复性好,在10~200nL/L范围内的线性拟合度高(R_2=0.999 6),检出下限为2.584nL/L/m,为SF6绝缘设备分解组分中痕量CS_2的在线监测提供了技术支持。

SF6 has been widely used as insulating gas in electrical insulation equipment.The research of its decomposition components is an important content for the equipment fault diagnosis and online monitoring.CS2 is one of the common SF6 decomposition components under the solid insulation defects.CS2 has absorption spectra in the UV band of 190~210nm.Based on the ultraviolet differential absorption spectroscopy(UV-DOAS),the UV spectrum detection platform was established.Firstly,the UV absorption spectrum of CS2 was obtained by experiments.Baseline deduction and wavelet processing methods were used to extract the effective signal in the absorption spectrum,which eliminated high and low frequency noise in the spectrum.Then,the spectral information is converted to the frequency domain by fast fourier transformation(FFT),and the linear relationship between the gas concentration and the spectral frequency domain eigenvalue was gained.The detection method of CS2 shows good linearity(R2=0.999 6)in the range of 10~200nL/L and satisfactory repeatability.The detection limit is 2.584nL/L.The method shows a potential for on-line monitoring of trace CS2 in decomposition components of SF6 insulation equipment.