苯并三氮唑对变压器绕组硫腐蚀抑制机理的分子模拟研究
Research on the Mechanism of Inhibition of Sulfur corrosion on Transformer Winding by Benzotriazole based on Molecular Simulation

摘 要：硫腐蚀现象对变压器绝缘性能的破坏不容忽视，其中腐蚀性硫化物与铜绕组作用产生的硫化亚铜是导致绝缘性能降低的一个重要原因。在变压器内部氧和有氧的情况下，硫化亚铜的生成主要是因为腐蚀性硫化物与铜或者与氧化亚铜发生了一系列反应。为深入研究铜缓蚀剂苯并三氮唑(BTA)对铜绕组的缓蚀机理，采用分子模拟技术分析了BTA分子与铜晶体的电荷密度分布和态密度分布；同时利用过渡态搜索、红外光谱研究了BTA分子与氧化亚铜的反应过程。结果表明： 加入BTA分子前后的铜表面态密度分布发生了变化，并且利用电荷密度分布图说明BTA分子与铜晶体形成了配位键；同时分析了BTA与氧化亚铜反应前后红外光谱的差异，发现BTA分子的结构已发生改变，与氧化亚铜形成了共价键。以上模拟结果说明BTA分子对铜和氧化亚铜有保护作用，能够抑制腐蚀性硫化物对铜绕组的腐蚀。
Abstract：Sulfur corrosion has great damage to the insulation performance of transformer and one of the most important reasons for the reduction of insulation is cuprous sulfide, which is produced by corrosive sulfur and copper winding reaction. A series of reaction of corrosive sulfur and copper or cuprous oxide is the main cause to generate cuprous sulfide in transformer, representing anaerobic and aerobic conditions respectively. In order to deeply study the corrosion inhibition mechanism of benzotriazole on copper windings, electronic density difference and density of states between benzotriazole and copper were analyzed by molecular simulation technology. Meanwhile, reaction between benzotriazole and cuprous oxide were researched through transition state search and infrared spectrum. The results show that the distribution about density of state of the copper surface has changed. Moreover, we can obtain the benzotriazole molecule form a coordination bond with the copper crystal from charge density distribution. By the analysis of infrared spectrum difference between benzotriazole and curprous oxide before and after reaction, we know that the structure of benzotriazole molecule has changed and form covalent bond with cuprous oxide. The above simulation illustrate that benzotriazole molecules have protective effects on copper and curprous oxide, at the same time, preventing copper windings from corroding by corrosive sulfide.