Traction power substation balance and losses estimation in AC railways using a power transfer device through Monte Carlo analysis

Abstract

The high dynamic power requirements present in modern railway transportation systems raise research challenges for an optimal operation of railway electrification. This paper presents a Monte Carlo analysis on the application of a power transfer device installed in the neutral zone and exchanging active power between two sections. The main analyzed parameters are the active power balance in the two neighbor traction power substations and the system power losses. A simulation framework is presented to comprise the desired analysis and a universe of randomly distributed scenarios are tested to evaluate the effectiveness of the power transfer device system. The results show that the density of trains and the relative branch length of a traction power substation should be considered in the evaluation phase of the best place to install a power transfer device, towards the reduction of the operational power losses, while maintaining the two substations balanced in terms of active power.

Double-Side Feeding and Reactive Power Compensation Using the Railway Interline Power Flow Controller

“…The current associated with the transferred power increases the losses in one section and reduces them in the other section; thus, there are conditions for which the total losses can be smaller with the RIPFC than without it. It should be mentioned that additional work related to the sp-RPC/PTD/RIPFC system has been performed using statistical models and probability distributions, with the general conclusions being very similar to the ones discussed here [16].…”

“…The two chosen scenarios demonstrate the RIPFC's capabilities in terms of reactive power compensation and active power transfer between different sections. The resultant power losses are higher than in the base scenario (no compensation); however, railway operations in real conditions contain a much larger number of scenarios, for which in some of them, the global losses will become smaller when compensation is made, as shown in [16].…”

“…An extensive probabilistic analysis (100,000 cases) was carried out in another research study by the authors of [16], in which the factors considered most-relevant to influencing losses in the system were the type of SST (sparse or dense in terms of the number of trains supplied) and the length of the branch (short or long). The performed analysis used different variables: number of trains in the branch, trains' apparent power and power factor, branch length, and distance to the SST; all the variables were fitted with probability density functions.…”

“…The system losses included the catenary losses and the RIPFC losses (efficiency level, constant losses and power-dependent losses). The outcomes of the study in [16] in terms of the sparsity/density of the SST type are as follows:…”

“…Therefore, a power-electronics-based converter system connecting the two sections could manage both active and reactive power at the neutral zone [13][14][15]. This converter has been designated by several names: sectioning-post rail power conditioner (sp-RPC) [11], power transfer device (PTD) [15,16], and railway interline power flow controller (RIPFC) [17], which is the designation adopted in this work. The RIPFC system can play an important role in those scenarios, and some of them will be addressed in the following.…”