The Influence of Bending Stress on the Sulfur Corrosion of Copper Winding

In the operation of transformer, most copper winding is in bending state, and bending stress was a factor which could certainly influence the corrosion of copper winding. In this paper, copper winding was firstly bent with different angles. Then, the corrosion behaviors of the copper samples have been investigated in mineral oil containing various concentration of corrosive sulfur. The results show that bending stress did influence the sulfur corrosion. It will accelerate corrosion of copper winding. Moreover, the properties of insulating oil could be seriously affected. With the increasing of the bending angles, the copper presented increasing dielectric loss and reducing breakdown voltage.