Use of converters for feeding of AC railways for all frequencies

Abstract

Railways are the most energy-efficient land-based mode of transport, and electrification is the most energy-efficient way to power the trains. There are many existing solutions to supply the trains with electricity. Regardless of which particular technology is chosen, it is beneficial to interconnect the public power grids to grids supplying power to the railways. This paper shows that the most efficient, flexible, and gentle-for-the-public-grid way of doing that is through powerelectronics-based power converters. Converters offer great benefits regardless of whether the overhead contact lines are of DC-type or AC type, and regardless of the AC grid frequency. This paper presents neither new theory nor new experimental results. Based on already available information, this paper presents logical arguments leading to this conclusion from collected facts. Over time what used to be advanced and high-cost equipment earlier can nowadays be purchased at reasonable cost. It is obvious that for most electrically-fed railways, the use of modern power converters is attractive. Where the individual trains are high consumers of energy, the railway gradients are substantial, and the public grids feeding the railway are weak, the use of converters would be technically desirable, if not necessary for electrification.It is expected that more high-speed railways will be built, and more existing railways will be electrified in the foreseeable future. This paper could provide some insights to infrastructure owners and decision makers in railway administrations about value additions that converter-fed electric railways would provide.

Power quality phenomena in electrified railways: Conventional and new trends in power quality improvement toward public power systems

“…In this method, the overhead catenary lines are sectionized in electrically isolated parts to avoid short circuits between phases. The non-electrified zones are called the neutral sections (NSs), and their length varies between several meters up to some kilometers [13]. Each zone along the catenary line is a single-phase one and the alternation between phases normally occurs at each traction substation.…”

High-voltage DC-feeder solution for electric railways

“…This is because it is rare that converter stations are being used for feeding them [6]. Without converters, the loads are asymmetrical on the three-phase-grid.…”

“…Using a transmission line with distributed active converters would allow double fed catenaries reducing voltage drops and reducing the required capacities of each individual substation [6].…”

A rotary frequency converter model for electromechanical transient studies of 1623 Hz railway systems

“…Because the frequency in the railway grid differs from the one in the public power grid, conversion of frequency is needed. This conversion can either be done by using a Rotary Frequency Converter (RFC) or a Static Frequency Converter (SFC) [2,3,4,5]. The RFC is essentially a three-phase motor and a single phase generator mounted on the same mechanical shaft.…”