Reliability Assessment of the External Power Supply in Electrified Railways With Weak Power Sources

Reliable external power supplies guarantee the safe and reliable operation of electrified rail-ways. Once the external power system fails, it disrupts the normal operation of trains and, especially for railways supplied by weak external power sources, may well incur serious accidents. Therefore, this paper proposes a reliability evaluation method of external power supplies of electrified railways with weak external power sources. Firstly, a weak external power system of electrified railways is modelled. Then, system operational states are analyzed by integrating Monte Carlo simulation with the DC optimal power flow (OPF) algorithm considering system node weight coefficients. Finally, reliability evaluation metrics are defined to quantify the reliability of both power system nodes and traction substations. A case study of a typical weak external power system supplying the electrified railways is presented to demonstrate the proposed method. Results show that the method can effectively quantify the reliability of the external power supply of electrified railways. Meanwhile, the DC OPF algorithm considering weight coefficients can significantly improve the reliability of critical loads, and thus improving the reliability of traction substations and electrical trains. The proposed method can provide valuable guidelines for the planning and designing of electrified railways supplied by weak power sources.