SF6电流互感器绝缘缺陷的放电及气体分解特性

选取铝筒均压型和电容屏均压型的500 kV SF₆电流互感器（CT）试品,研究了绝缘子沿面缺陷和复合缺陷下的放电及气体分解特性,并分析了缺陷类型、放电路径长度和采气位置对该特性的影响。发现相位分辨率的脉冲序列（PRPD）谱图是气体分解特性研究的良好辅助手段,改良设计的采气口检测结果更准确。绝缘介质缺陷的典型特征是含C物质（CF₄、CS₂）的生成。绝缘子沿面缺陷下SO₂含量高于SO₂F₂,S₂OF₁₀的含量增长率较低,且放电路径长度会影响典型产物的种类。复合缺陷下SO₂F₂和SO₂的含量增长率较高,S₂OF₁₀的含量增长率相对低。

Discharge and Gas Decomposition of Typical Insulation Defects in 500 kV SF6 Current Transformer

Two 500 kV SF₆ CTs with aluminum cylinder grading structure and cone capacitor grading structure are selected to analyze discharge and gas decomposition characteristics of insulator surface defect and combining defect. The influences of defect type, discharge path length and sampling positions are discussed. It is found that measuring PRPD is an effective assistant method for gas analysis. The detection results of the improved sample port are more accurate than that of regular one. Typical gas decomposition products of the insulation material related defects are CF₄ and CS₂. In insulator surface defect, concentration of SO₂ is higher than SO₂F₂; the growth rate of S₂OF₁₀ concentration is relatively low; types of decomposition products vary with discharge path length. In the combining defect, the growth rates of SO₂F₂ and SO₂ are relatively higher than that of S₂OF₁₀.