Electrified Railway Research Articles

Electrotribological behavior of Cu−Ag−Zr contact wire against copper-base strip

Cu−Ag−Zr alloy has an excellent combination of mechanical strength and electrical conductivity, and is a promising contact wire material for high-speed electrified railways. An investigation of the electritrobological behavior of Cu−Ag−Zr wire is presented here. Wear tests are conducted under laboratory conditions with a specified sliding wear tester that simulated train motion under an electrical current applied across the sliding interface. The Cu−Ag−Zr alloy wire is slid against a copper-based powder metallurgy strip used in railway systems under unlubricated conditions. Worn surfaces of the Cu−Ag−Zr alloy wire are analyzed by scanning electron microscopy (SEM) and energy dispersive X-ray spectrum (EDS). Within the studied range of electrical current, normal pressure, and sliding speed, the wear rate increases with increasing electrical current and sliding distance. Adhesive wear, abrasive wear, and electrical erosion are the dominant mechanisms during the electrical sliding processes. Compared with a Cu−Ag contact wire under the same test conditions, the Cu−Ag−Zr alloy wire has much better wear resistance.

A Novel Active Power Quality Compensator Topology for Electrified Railway

To improve the power quality of traction power system, a novel active power quality compensator (APQC) and a new compensating currents detection method are proposed. The APQC consists of a three-phase voltage source converter and a Scott transformer. The Scott transformer, taken as an isolation transformer, not only connects the three-phase converter to the traction power system, but also converts the traction power system to a nearly balanced three-phase power system. Therefore, a general three-phase converter could be used in APQC. Regarding the traction substation as a compensating object, the power quality of a traction substation can be improved integrally. Simulation and prototype experimental results show that the proposed APQC is able to compensate reactive power, harmonic, and negative-sequence currents in two feeders of a traction substation.

Transportation for Hong Kong Requires Solutions to Issues and Problems

Accommodating the rapidly expanding Hong Kong population on a rugged terrain of limited area demands a solution to many transportation issues and problems. The old urban area is growing and being modernized. In addition, many new towns are planned in formerly rural areas. A sophisticated transport system has been developed during the past three decades that helps to integrate the old and new communities together as well as to improve the quality of life in this dynamic metropolitan city. The system comprises several major traffic modes that complement one another, including a high-capacity road network, an electrified suburban railway, a busy underground metro, a modern light rail, and a traditional street tramway. Many major bridges and tunnels are built with advanced technology, many of which can be considered a challenging project of its own.

Wear properties of tungsten carbide and aluminium oxide sintered materials: Wear, Vol 12, No 1 (July 1968) pp 17–25

This paper reports the study of the sliding wear behavior of the Cu–Ag–Cr wire. Cu–Ag–Cr alloy is a promising contact wire material for high-speed electrified railways, which has an excellent combination of mechanical strength and electrical conductivity. Wear tests were conducted under laboratory with a special sliding wear apparatus, which simulated the tribological conditions of sliding current collectors on overhead wires in the railway system. The Cu–Ag–Cr alloy wire was slid against a copper-based powder metallurgy strip under unlubricated conditions. The same strip as those in the train systems were used. Worn surfaces of the Cu–Ag–Cr alloy wire were analyzed by scanning electron microscopy (SEM) and energy dispersive X-ray spectrum (EDS). Within the studied range of electrical current, normal pressure and sliding speed, the wear rate increased with the increasing electrical current and the sliding distance. Compared with a Cu–Ag contact wire under the same conditions, the Cu–Ag–Cr alloy wire had much better wear resistance. Adhesive wear, abrasive wear and arc erosion were the dominant mechanisms during the electrical sliding processes.

The Probability Density Function for Unbalancing Loads on A. C. Electrified Railways

The Probability Density Function for Unbalancing Loads on A. C. Electrified Railways

Some recent earth‐resistivity measurements in the United States

Introduction—The problem of constructing and maintaining in the same region networks of lines for the transmission of power and of intelligence in such a way as to minimize the electrical interference between these two types of facilities is of a complicated nature. One of the controlling factors in determining the severity of any situation may be the effects of currents returning through the Earth. In power‐supply systems, as usually designed and operated, the current in the Earth under normal conditions is quite small, but occasionally short circuits to ground occur which increase this current sometimes to hundreds of amperes. In electrified railways a substantial portion of the propulsion‐current returns to the source through the Earth, and as in power‐supply systems, this earth‐current may be greatly increased by short circuits to ground.

An electrified railway substation of the Pennsylvania railroad

This paper contains a description of one of the out-door substations of the Philadelphia-Wilmington electrification of the Pennsylvania Railroad, recently placed in service. It describes the initial installation of apparatus provided in the substation for the present suburban electrification, as well as the steps taken to accommodate the additional apparatus necessary for the through electrification when it takes place. The location and control of the substation are described as well as the types of protective apparatus utilized and the method of operation. Attention is called to certain operating necessities which control the design and location of a substation of this character. The means provided for handling the heavy apparatus into and out of a substation of this character and the facilities for handling, cleaning, and restoring oil to the different pieces of apparatus are described in some detail.