SF_6绝缘气体光谱信号的最佳小波基基线校正算法

Baseline Correction Method for Spectrum Signal of SF_6 Insulating Air with Optimum Wavelet Basis

SF6气体作为优异的绝缘介质和灭弧介质,被广泛地应用于各种电力设备中。为了对SF6绝缘气体成分进行监测以保障电力安全,针对光谱检测法,提出一种基于最佳小波基的基线校正算法。该算法按照能量集中准则构造代价函数,从光谱信号小波包中选取最优小波基对信号进行时频域表示;然后通过阈值法去除光谱信号中的强谱信息,以排除其对连续谱拟合的影响。对剩余信号进行最小二乘拟合得到连续谱,并从原谱中去除连续谱,即得所需的线谱。基线校正处理后的线谱强度能够真实反映光谱谱线强度,提高了定量分析的精度。对存在漂移现象的SF6气体吸收光谱进行实验分析,结果表明,该算法能准确有效地估计并校正基线,拟合精度高于迭代小波基线校正算法。

SF6 gas has been widely used in the power equipments as an excellent electric insulating and arc-quenching medium.In the present paper,a baseline correction method based on the optimum wavelet basis for spectrum detection is proposed to measure the composition content of the SF6 insulating gas to secure the power safety.In this method,the optimum wavelet basis is selected in the wavelet packet according to constructor function on the energy concentration criterion to express the spectrum signal in the time-frequency domain.Then the strong spectrum composition is removed from the spectrum signal with the threshold method to eliminate the interference with the continuous spectrum fitting.Finally we remove the continuous spectrum which is fitting result from the origin spectrum and obtain the useful signal of line spectrum.The intensities of spectral line processed with the proposed algorithm could reflect the concentration of the conponents to be measured in SF6 gas.Experiments to analyze the absorption spectrum of the SF6 insulating gas mixture show that the proposed algorithm can estimate and correct the drifting baseline accurately,and its performance is better than the algorithm based on iterative wavelet.