Research on the Identification Method of Vulnerable Lines along the CZ Railway Considering the Uncertainty of Traction Load

Aiming at the extremely weak power grid along the CZ railway and the uncertainty of forward and reverse traction loads, a method for identifying vulnerable lines of power system considering the uncertainty of traction loads is proposed. Firstly, the probabilistic power flow section of the system is calculated using the simulated high-speed railway load curve. Then, a high-risk power flow section discrimination algorithm is constructed using random matrix theory to extract high-risk power flow sections. Immediately after that, the correlation network of the power grid is established by using the dual graph under the high-risk section, and then the weighted z-index is proposed, which is applied to the correlation network to identify the vulnerable lines. Finally, the accuracy and effectiveness of the proposed method are verified in the simulation of the power grid along the CZ railway.

I. Introduction

Efforts of a large number of scientific research and technical personnel has been inj ected in the CZ railway in China. The conventional load of the power grid along the CZ railway is relatively small, so that the railway traction load will become the main load in this area. In addition, the huge terrain fluctuations along the CZ railway make the load of the line not only has shock and random fluctuation, but also may have frequent and large regenerative braking power different from the conventional line load, which aggravates the uncertainty of the load side. On the other hand, the external power grid conditions are extremely weak, and some areas lack the support of strong power grid. Therefore, in the case of high-proportion traction load connection to the grid in the future, the system will suffer from frequent forward and reverse uncertainty currents, which will have an unpredictable impact on the stability of the system. In order to avoid the occurrence of cascading failures, the research on system vulnerability is imminent, and the identification of vulnerable lines in the system is a key problem that needs to be solved urgently with the current traction load connected.