Application Of Insulation Condition Monitoring Technique To Datong-Qinhuangdao Railway Traction Substations

With the development of heavy railway transportation, traction overload phenomenon is become more frequent, and the impact of overload is also more obvious. Datong-Qinhuangdao(Da-Qin) railway which uses the advanced heavy load technology and equipments is the avenue of modernization coal transportation. The high traffic density and heavy load are the main characteristics of Da-Qin railway. Therefore, the probability of insulation failure is higher than others in traction substations, and the rapid aging of insulating condition eventually leads to power failure, which causes a long interruption of rail transport and great losses. So it is very important to master the operation condition of primary equipment in traction substation timely.The winding connection method and work feature of traction transformer in Da-Qin railway is described, and several reasons of insulation aging in traction transformer are investigated, including thermal aging, electrical aging, mechanical aging, and aging caused by environmental factors. The monitoring methods of primary equipment in traction substation are researched, including traction transformer, bushing, instrument transformer, surge arresters and so on. The principle and structure of online monitoring system of traction transformers and capacitive equipment is also researched. The fault diagnosis and prediction expert system is established.According to the characteristics and type of insulation failure in traction substation, online condition monitoring system in Qian’an traction substation of Da-Qin railway is carried out, monitoring the dissolved gases in transformer oil, leakage current of the capacitive device and so on. Then the data is analyzed and calculated to obtain insulation condition parameters, such as dielectric loss factor, resistive current and total current and fault gases content in transformer oil. Based on the insulation condition parameters and fault diagnosis expert, the insulation condition of high-voltage equipment of traction substation correctly and predict the potential insulation failure is assessed, providing the maintenance program for engineering staff.