工频电压下聚乙烯表面动态电荷分布的研究  

Study on Dynamic Surface Charge Distribution of PE Under Power-frequency Voltage

作　　者：郭旺 张波[1] 韩文虎 孙宇豪 穆海宝[1] 张冠军[1] GUO Wang;ZHANG Bo;HAN Wenhu;SUN Yuhao;MU Haibao;ZHANG Guanjun(State Key Laboratory of Electrical Insulation and Power Equipment,Xi’an Jiaotong University,Xi’an 710049,China)

机构地区：[1]西安交通大学电力设备电气绝缘国家重点实验室,西安710049

出　　处：《高压电器》2023年第9期76-83,共8页High Voltage Apparatus

基　　金：国家自然科学基金(11775175);西安交通大学基本科研业务费自由探索与创新项目(xzy022021020)。

摘　　要：聚合物材料被广泛应用于电气设备的电气隔离和机械支撑中,在高压电场作用下,大量积聚在聚合物表面的电荷会引发局部电场畸变和沿面闪络,威胁设备安全。文中搭建了具有反射式拓扑结构的Pockels效应表面电荷动态测量平台,原位观测了单极性电压、单周期工频电压和多周期工频交流电压作用下聚乙烯薄膜表面电荷二维分布的动态演变。结果表明,基于Pockels效应的测量方法可以观测到0.5 s内的电荷积聚、扩散和消散过程,这是机械扫描式的静电探头法无法获得的;在正极性和负极性电压作用下,聚乙烯表面只沉积对应极性的电荷,其积聚、扩散和消散过程的持续时间大约为0.5 s,70%~85%积聚电荷量会在0.4 s内消散。对比施加不同极性起始的正弦交流电压情况下聚乙烯表面电荷演变,发现仅正极性起始的工况下会出现正负电荷共存的分布样貌。通过观测连续10个工频周期下聚乙烯表面电荷的行为,发现聚合物表面电荷积聚至少需要经历3~4个工频周期才能稳定,在此过程中表面电荷分布区域逐渐收缩。该研究结果对于直观理解交流电压作用下聚合物电荷积聚的演变过程有重要的参考价值。Polymeric materials are widely used for electrical insulation and mechanical support in electrical apparatus.Under the high voltage electric field,the large number of charges accumulated on the polymeric surface tend to cause local electric field distortion and surface flashover,considerably threatening the safety of equipment.In this paper,a reflective-type surface dynamic charge measurement platform based on Pockels effect is set up to observe the evolution of two-dimensional surface charge distribution on polyethylene under unipolar voltage,single cycle power frequency voltage and multi-cycle power frequency voltage.The results indicate that the measurement method based on Pockels effect can observe the charge accumulation,diffusion and dissipation processes within 0.5 s,which cannot be obtained by the traditional electrostatic probe method.Under the positive and negative polarity voltage,only the charge of the corresponding polarity is deposited on the polyethylene surface.The duration of the charge accumulation,diffusion,and dissipation process is about 0.5 s,and 70%~85%of the total accumulated charge is dissipated from the surface within 0.4 s.By comparing the evolution of the surface charge under sinusoidal AC voltage with different polarity inception,it is found that the coexistence of positive and negative charges occurs only for positive polarity inception.The dynamic behavior under 10 consecutive power frequency cycles reveals that it takes at least 3~4 cycles for surface charge accumulation to evolve into a stable state,with the gradual shrinking charging regions during this period.The research results have important reference value for intuitive understanding the evolution process of polymer charge accumulation under AC voltage.

关 键 词：沿面耐电 表面动态电荷 泡克尔斯效应 针板电极 工频交流 

分 类 号：TQ325.12[化学工程—合成树脂塑料工业]