Effect of Wet Condition on the Wear Performance of Carbon Strip and Metal Contact Wire with Electric Current

Pantograph is the only device used by trains to obtain power from overhead contact line of high-voltage transmission. The abrasion of the pantograph carbon strip in current-carrying friction is related to various working environments such as rainfall. Carbon strips absorb water to varying degrees in wet condition due to its own pore structure of the material. Extensive field experience shows that the abrasion of carbon strips has increased sharply in wet weather, resulting in its service time is much lower than expected. In severe cases, the abrasion failure of strips will affect the stable current collection during the train operation. Abnormal failure of the contact pair makes the current-carrying friction system unable to meet the real and long-term demands. Therefore, it is of great significance to study the electrical friction behaviors of pantograph carbon strip in the wet condition for ensuring the safe operation of trains and improving the national economy. In this paper, by quantitatively controlling the water content added to the carbon strip to simulate different levels of wet conditions. Using a self-made sliding reciprocating current-carrying friction test bench to study the deterioration rule and damage mechanism of water on the current interface between carbon strip and metal contact wire through changing the water content of the carbon strip, current and normal load. The results show that under the condition of low current, the wear volume and friction coefficient of carbon strips increase first and then decrease with increasing water content added to the strips. It indicates that there is a range of water content, which makes the wear more serious. In addition, under the same water content of the strip, the abrasion situation becomes more serious with the increase of current, and the material transfer phenomenon of copper contact wire on the surface of strips is more obvious. And the increase in normal load tends to slow down the degree of wear. The research content has certain reference significance for the analysis of pantograph strip abrasion failure in wet areas.