纳米绝缘油交流击穿特性分析

绝缘油填充于各型变压器、电力电容器等充油电力设备中,起绝缘、导热、灭弧等作用,在电力系统中有着广泛地应用。随着输电电压等级的不断提高,对绝缘油提出了更高的要求,因此提高绝缘油性能,对中国特高压发展具有重要意义。由于纳米粒子的尺寸效应,传统的小桥击穿理论可能将不再适用,为改善绝缘油的性能提供了新的途径。笔者研究了纳米绝缘油的制备方法,并对不同质量分数纳米粒子的绝缘油进行了交流击穿电压实验。研究结果表明,适当质量分数的纳米粒子能有效地改善绝缘油的交流击穿特性。应用纳米粒子球形介质极化模型,计算了粒子表面产生的势阱,并指出了纳米粒子改善绝缘油击穿特性和添加纳米粒子过多导致绝缘油的击穿性能降低的原因。

AC Breakdown Characteristics of Nanometer Insulating Oil

The insulating oil filled in each type transformer,power capacitor and other oil-filled power equipment, widely applied in power system,is used to insulation,heat conduction and arc extinguishing,etc.With the continuous improvement of the transmission voltage level,much higher requirements have been proposed for the insulating oil,therefore improving the performance of insulating oil has important significance for the development of Ultra-High Voltage.As the nano-particles size effects,the traditional bridge breakdown theory is no more applicable,thus a new approach has been provided for improving the insulating oil.In this paper,the preparation methods of nanometer insulating oil are investigated,and the AC breakdown experiments are conducted for the nanometer insulating oil with different concentrations of nano-particles.The experimental results show that adding certain concentration nano-particles can effectively modify AC breakdown characteristics of insulating oil. According to spherical dielectric nano-particles polarization model,the depth of surface potential well are calculated,it is pointed out the reasons of the improvement breakdown characteristics of nanometer insulating oil and excess nano-particles leading to decreasing of the breakdown performance.