中文摘要：

为了分析冲击电压下GIS腔体内局部放电信号的特征．将一种时频变换理论即二次型短时傅立叶变换应用于局放脉冲序列的分析，得到信号在时频平面的能量分布和变化规律。通过对含噪声局放脉冲序列时频变换的仿真研究，有效地提取了放电脉冲。另外，在实验室对220kVGIS母线段进行了尖刺缺陷模型的安装和冲击耐压下局放检测．对实测数据进行了时频分析。验证了二次型短时傅里叶变换在局放信号处理中的有效性，得到了信号时频谱图在不同长度窗函数处理下的变化规律。

英文摘要：

In order to analyze the characteristics of signals of partial discharge （PD） in GIS under the impulse voltage, a kind of time-frequency transform theory called the quadratic short-time Fourier transform was applied in analysis of the PD pulse sequence to get the distribution of energy and variation law of signals in the time-frequency plane. In this research, the time-frequency transform of a kind of typical PD pulse sequence containing noise was simulated, which showed that PD pulse could be extracted efficiently. Besides, a kind of spikes defect model was installed in the bus segment of 220 kV GIS and the PD of GIS under impulse voltage was detected. By time-frequency analysis of experiment data, it can be found that the theory of quadratic short-time Fourier transform can be applied in analysis of PD signals efficiently and the variation law of time-frequency spectrogram was affected by the length of window function.