Sun Potao, Sima Wenxia, Zhang Dingfei, Jiang Xiongwei, Zhang Huangjing, Yin Ze
State Key Laboratory of Power Transmission Equipment & System Security and New Technology, Chongqing University, Chongqing 400030, China.
College of Engineering Materials, Chongqing University, Chongqing 400030, China.
Nanomaterials (Basel). 2018 Jul 7;8(7):504. doi: 10.3390/nano8070504.
Nano-modification is a prospective method for improving the electrical properties of transformer oil. In most situations, transformer oil combined with cellulose paper is used to construct an insulation system for power equipment, such as power transformers. However, the influence of nanoparticles on the electrical performance of oil-impregnated paper is still unclear. Therefore, in this paper, we identify the failure characteristics of both fresh and nano-modified oil/paper. Specifically, the accumulative failure characteristics of nano-oil-impregnated paper (NOIP) are experimentally determined. The space charge distribution and trap characteristics of fresh paper and NOIP were measured, and the effect of nanoparticles on the space charge behavior are then analyzed. Finally, we measure the microstructure of fresh paper and NOIP subjected to repeated impulses. The test results indicate that nano-titanium oxide (TiO₂) particles have a limited effect on the breakdown voltage of NOIP. However, the particles can dramatically improve the resistant ability of NOIP against repeated impulses. For the NOIP with a nano-concentration of 0.25 g/L, the improvement reaches 62.5% compared with fresh paper. Under repeated applications of impulse voltages, the space charge density of NOIP is much lower than that of fresh paper. The deep trap density of NOIP is much higher than that of fresh OIP, whereas shallow trap density is relatively lower. Micropores are generated in paper insulation subjected to repeated impulses. The amount of the generated micropores in NOIP is lower than that in fresh paper. Nano-TiO₂ particles suppress the accumulation of space charge in the oil paper insulation, which weakens the electric field distortion in the dielectric. However, nanoparticles reduce the accumulative damage caused by repeated impulses. The above two points are considered the main reasons to improve the resistant ability against repeated impulses.
纳米改性是一种改善变压器油电气性能的前瞻性方法。在大多数情况下，变压器油与纤维素纸结合用于构建电力设备（如电力变压器）的绝缘系统。然而，纳米颗粒对油纸电气性能的影响仍不明确。因此，在本文中，我们确定了新鲜的和纳米改性的油/纸的失效特性。具体而言，通过实验确定了纳米浸油纸（NOIP）的累积失效特性。测量了新鲜纸和NOIP的空间电荷分布和陷阱特性，然后分析了纳米颗粒对空间电荷行为的影响。最后，我们测量了经受重复脉冲的新鲜纸和NOIP的微观结构。测试结果表明，纳米二氧化钛（TiO₂）颗粒对NOIP的击穿电压影响有限。然而，这些颗粒可以显著提高NOIP对重复脉冲的耐受能力。对于纳米浓度为0.25 g/L的NOIP，与新鲜纸相比，其改善幅度达到62.5%。在重复施加脉冲电压的情况下，NOIP的空间电荷密度远低于新鲜纸。NOIP的深陷阱密度远高于新鲜浸油纸（OIP），而浅陷阱密度相对较低。在经受重复脉冲的纸绝缘中会产生微孔。NOIP中产生的微孔数量低于新鲜纸。纳米TiO₂颗粒抑制了油纸绝缘中空间电荷的积累，减弱了电介质中的电场畸变。然而，纳米颗粒减少了由重复脉冲引起的累积损伤。以上两点被认为是提高对重复脉冲耐受能力的主要原因。
