Study on Electrical Parameters Calculation of Traction Network Based on the Multi-conductor Loop Circuit Method

Considering the actual transmission and backflow conductors regarding earth return, this paper proposed a traction network impedance calculation method based on multi-conductor loop circuit. At First, according to transmission and return function, the traction network conductors including the earth is classified; subsequently, various loop circuits are structured for different transmission and backflow conductors. an‎d the impedance matrix constituted by self-impedance and mutual impedance of each loop circuit are calculated to deduce the loop circuit current distribution coefficient and the system comprehensive impedance. Then, since overhead return condition exists in actual traction network, the impact of the earth on the loop circuit of overhead conductors is analyzed. That is, the impedances calculated by overhead conductor loop method, simplified Carson formula and Dubanton formula are compared, an‎d the results indicates that the influence is negligible. Finally, based on the Yu-Qian railway, the unit-length traction network integrated impedances calculated by the loop circuit method and the classical Carson theory are compared; combining the short circuit experiment of Feng-Shibi feeding arms in Yu-Li HSR, the validity for performing the calculation and analysis of electrified railway based on loop circuit method is further validated. The study illustrates that the method proposed is able to perform a favorable description for traction power supply system and realize accurate calculation of traction network integrated impedance, which has certain rationality and engineering practicability.