A Novel Power Flow Algorithm for Traction Power Supply Systems Based on the Thévenin Equivalent

Abstract

Abstract:With the rapid development of high-speed and heavy-haul railways throughout China, modern large power locomotives and electric multiple units (EMUs) have been applied in main railway lines. The high power requirements have brought about the problem of insufficient power supply capacity (PSC) of traction power supply systems (TPSSs). Thus, a convenient method of PSC assessment is meaningful and urgently needed. In this paper, a novel algorithm is proposed based on the Thévenin equivalent in order to calculate the PSC. In this algorithm, node voltage equations are converted into port characteristic equations, and the Newton-Raphson method is exploited to solve them. Based on this algorithm, the PSC of a typical high-speed railway is calculated through the repeated power flow (RPF). Subsequently, the effects of an optimized organization of train operations are analyzed. Compared to conventional algorithms, the proposed one has the advantages of fast convergence and an easy approach to multiple solutions and PV curves, which show vivid and visual information to TPSS designers and operators. A numerical analysis and case studies validate the effectiveness and feasibility of the proposed method, which can help to optimize the organization of train operations and design lines and enhance the reliability and safety of TPSSs.

High-Speed 2 × 25 kV Traction System Model and Solver for Extensive Network Simulations

“…Each profile represents a single run of a train on a specific track which may consist of multiple of sections. A similar approach can be found in [14], [30], [29], [35], [31], [22], [33], [16], [34].…”

“…The system is much lighter from the computational point of view, but the accuracy of the calculation is lower since the effect of the inductive couplings is not negligible. On the other side, many authors propose or use very complicated models considering the couplings as it can be observed for instance in [31], [32], [7], [8], [33], [19], [34]. These models are very accurate but also complex from the point of view of their computational burden, which is a very important drawback for making extensive calculations.…”

“…4 (left), the electrical model of the traction substation for the single-voltage and bi-voltage cases are depicted respectively. The presented model is equivalent to the one using two voltage sources with series impedances which has been widely used by many authors, see for instance the references [22], [16], [25], [34], [33].…”

Steady-state analysis of power distribution system with dynamic charging electric vehicles

“…Interestingly, a relevant research area, however, is railway electrification systems with a focus on electric locomotives. Most importantly, [10][11][12][13][14][15] carried out power flow analysis of electrified tracks, wherein several new power flow algorithms are introduced, based on which power supply capacity of traction power supply systems and voltage distribution in transmission systems can be analyzed. Another important research direction on trains, tramways, and buses is to apply regenerative braking energy and leverage the topology of the power supply system to enhance the system's e ciency and economic operation [1,16].…”

“…In addition, nowadays, the innovation tendency from traditional electrical systems towards smart grids reminds human beings of evaluating carefully the appropriate directions. The technical problems of electric railway systems may depend on the historical and economical specialties of countries and regions [10]. Therefore, the better solutions for improving this new transportation system are required.…”