Research on Fault Diagnosis and Protect Model for DC Traction Power Supply System Based on Traveling Wave Theory

The paper analyses the limitation of the differentiation i-delta I protection method. It puts forward traveling wave protection method for the DC power supply system that is based on interrelated characteristics of the traveling wave and the unit impedance of the transmission line. The traveling wave protection method overcomes the disadvantage of the traditional method in which the protection action is affected by the overall impedance of the circuit, and thus improves the reliability and sensibility of the relay protection system. A great number of field tests are carried out and the research results are satisfactory