【摘要】 金属化薄膜干式电容器作为光伏发电逆变器与电动汽车能源系统的核心部件，其服役性能将直接影响设备的运行稳定性。目前，针对交流干式电容器容值损失特性的研究大多集中于金属腐蚀导致的电极导电性能下降，较少关注由自愈等放电引起的表面电极退化现象。本文通过分析金属化薄膜表面宏观形貌与微观元素分布变化发现除自愈外，闪络放电会在自愈点周围形成丝状电极蒸发通道，并引发留边区域电极退化。基于纯聚丙烯薄膜沿面放电特性的对比实验，揭示了金属化薄膜自愈与沿面闪络放电具有相似的时频域特征，持续时间为0.7～1.0μs，频率峰值约为4～5 MHz，从而将两种放电类型称为电容损失放电，并分析其产生机制与演化特性。在此基础上，开发了一种基于图像处理的电极退化区域识别与定量分析方法，研究结果表明交流工况下自愈点面积较小，集中分布在0.5 mm~2以下，而77%的电极损失源于闪络放电诱发的电极大面积退化，构成电容损失的主导因素。本研究可用于金属化薄膜干式电容器的设计优化，提高光伏发电逆变器和电动汽车能源系统的运行稳定性和可靠性。更多还原

【Abstract】 The operational stability of the equipment is directly impacted by the service performance of metallized film dry capacitors, which are essential parts of electric car energy systems and photovoltaic power generation inverters. The majority of extant studies on the capacitance loss characteristics of AC dry capacitors focus on the degradation of electrode conductivity due to metal corrosion, with less attention paid to the degradation of surface electrodes caused by self-healing and other discharges. Surface electrode deterioration brought on by discharges like self-healing receives less attention. In addition to self-healing, flashover discharge will create filamentous electrode evaporation channels around the self-healing point and result in electrode degradation in the edge-leaving area, according to this paper’s analysis of the macroscopic morphology and microscopic element distribution changes on the metallized film’s surface. The self-healing of metallized films and the surface flashover discharge have comparable time-frequency domain characteristics, with a duration of 0.7-1.0 μs and a main frequency of roughly 4-5 MHz, according to comparative experiments of the surface discharge characteristics of pure polypropylene films. As a result, the two discharge kinds are referred to as capacitance loss discharge, and an analysis is conducted on their evolution and generation methods. In light of this, this work creates an image processingbased technique for locating and quantitatively assessing electrode deterioration zones. The findings of the study demonstrate that the region of self-healing points under alternating current conditions is small and concentrated below 0.5 mm~2.However, 77% of the electrode loss is attributed to the large-scale degradation of the electrodes induced by flashover discharge, which constitutes the dominant factor for capacitance loss. This study guides the design optimization of metalized film dry capacitors to improve the operational stability and reliability of photovoltaic power inverters and electric vehicle energy systems.更多还原