双向拉伸聚丙烯薄膜(Biaxially oriented polypropylene, BOPP)是目前金属化膜电容器的主流电介质材料，其介电、理化性能直接影响着电容器的运行特性与使用寿命。目前，针对BOPP在电容器内部复杂多物理场环境下的老化机制研究还不充分，电容器内部劣化机理尚不明确。本文开展BOPP在脉冲电场下的电热联合老化实验，测试不同老化条件下BOPP样品的击穿场强、电荷和陷阱、表面成分和形貌等特性，分析脉冲参数和环境温度对样品老化过程的影响。研究结果表明，脉冲频率为500 Hz，温度为60 °C老化条件下，脉冲电压幅值从1 kV增加到5 kV时，样品直流击穿场强从610 kV/mm下降为515 kV/mm；当脉冲电压条件固定，温度从40 °C升至100 °C时，击穿场强从630 kV/mm下降为490 kV/mm；在脉冲电压与环境温度的协同作用下，BOPP同时发生分子链的裂解与热氧反应两种老化过程，进而导致样品电气强度的下降，其中脉冲电压幅值和环境温度对BOPP电气性能的劣化影响最为显著。

Biaxially oriented polypropylene (BOPP) is the main dielectric material for metallized film capacitors, and its dielectric and physical and chemical properties directly affect the operation and service life of capacitors. At present, there is insufficient research on the aging mechanism of BOPP in the complex multi-physical field environment inside the capacitor, and the degradation mechanism of the capacitor is not clear. In this paper, an electro-thermal combined aging experiment of BOPP under pulsed electric fields was carried out. The breakdown field strength, charges and traps, surface composition and morphology of BOPP samples were tested under different aging conditions, and the impact of pulse parameters and environmental temperature on the aging process of the samples was analyzed. The results show that with the pulse frequency of 500 Hz and the temperature of 60 °C, the DC breakdown field strength of BOPP samples falls from 610 kV/mm to 515 kV/mm when the amplitude of pulse voltage increases from 1 kV to 5 kV. With the fixed conditions of pulse voltage, the breakdown field strength falls from 630 kV/mm to 490 kV/mm when the temperature increases from 40 °C to 100 °C. Under the synergistic effect of pulse voltage and ambient temperature, BOPP simultaneously undergoes two aging processes: molecular chain scission and thermal oxygen reaction, which leads to a decrease in the electrical strength of the samples. In all the aging parameters, the amplitude of pulse voltage and ambient temperature have the most significant impact on the electrical performance of BOPP.