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为了完善复合绝缘子的人工污秽试验方法，研究了染污硅橡胶试品的受潮过程。试品受潮期间监测污层表面泄漏电流，并提取了泄漏电流基波分量，结合试品受潮状态图像，综合分析泄漏电流变化趋势与污层受潮状态的对应关系。试验结果表明：泄漏电流幅值会受到污层表面放电现象的影响，然而泄漏电流基波分量主要取决于污层表面电导率，放电过程对泄漏电流基波分量幅值的影响较小。泄漏电流基波与全波的差异，体现了染污试品表面放电强度，以泄漏电流基波分量与全波的幅值比(以下简称幅值比)来表征污层表面的放电强度。放电强度与污层的受潮程度紧密关联，幅值比变化在试品受潮期间呈现出典型的阶段性，其第3阶段与污层的干区形成过程相对应，表明污层受潮程度趋于一种临界状态。在幅值比变化第3阶段附近进行升压闪络试验，试品污闪电压与污层憎水性能相关性良好。反之，若受潮时间设置不合理，试品污闪电压不能体现出污层的憎水性能差异。研究所得结论有助于理解复合绝缘子的受潮过程，为表征复合绝缘子的受潮状态提供了新思路。“,”1 In order to improve artificial pollution test method for composite insulators, wetting process of polluted silicone rubber samples was studied. Leakage current and its fundamental component were obtained during sample wetting. By using dirty layer image during wetting, correspondence between leakage current change and damp state of pollution layer was analyzed. Test showed that leakage current amplitude was affected by surface discharge. However, leakage current fundamental amplitude mainly depended on conductivity of pollution layer, rather than surface discharge. Difference between fundamental component and whole leakage current reflected surface discharge intensity, characterized with parameter Kh10, ratio of leakage current fundamental component and full wave amplitude. Discharge intensity closely related to damp state. Several typical stages of Kh10 change existed during wetting. Stage 3 of Kh10 was linked to dry band formation, showing that damp state of dirty layer was approaching to critical state. Near stage 3 of Kh10 for raising voltage flashover test, good correlation of flashover voltage and hydrophobicity of samples existed. However, flashover voltage could not reflect hydrophobicity difference of samples if wetting time setting was improper. This study is helpful for understanding wetting process of composite insulators, and provides a new approach to describe damp state of composite insulators.