ang Wang

Study on Characterization of Electrical Contact between Pantograph and Catenary

Perfect sliding contact which requires appropriate contact force between pantograph and contact wire is the key point to guarantee the stability of current collection in locomotive. In order to study on characterization of electrical contact between pantograph and catenary, first, a novel test apparatus of pantograph electrical contact has been developed according to the filed application. The apparatus can simulate laterally (zigzag) movement, vertical vibration and the flexible line contact between pantograph contact strip and contact wire. Then, electrical contact experiments are carried out using this apparatus. Characteristics of static contact resistance under various contact force and traction current are analyzed. A fitted formula for contact resistance is proposed which have two independent variables of contact force and traction current. Possible mechanism for variation of contact resistance is represented in microscopic view of contact surface. It is demonstrated that the static contact resistance decreases with the contact force and traction current increasing.

Study on the Performance of Integrated Grounding Line in High-Speed Railway

The high-speed railway (HSR) has become more important in modern society. However, the rail potential rises remarkably, because of the high leakage resistance to earth with the use of ballastless track and huge traction return current on rail. That is a serious threat to passengers and equipment safety along the railway. Integrated grounding line (IGL) can decrease rail potential obviously. Its structure is quite different from grounding rods in non-HSR substations. Meanwhile, IGL goes along the entire railway, and its parameters optimization can obtain enormous economic benefits and significantly decrease the workload of laying the line. Therefore, the performance of IGL should be studied in detail. With assessment of grounding impedance and shunting coefficient, the relationships between IGL parameters and its performance have been analyzed. Related experiments had also been carried out on the SUI-YU railway (the first ballastless HSR in China). Compared with the theoretical results, the differences were less than 15% and 5% for grounding impedance and shunting coefficient, respectively. With the analyzing results, some pieces of advice have been proposed.

Pantograph Arcing's Impact on Locomotive Equipments

Pantograph arcing is a common phenomenon when the pantograph head and contact wire have sliding electrical contact. With the speed up of trains, the arcing becomes particularly serious for the irregularity of catenary and tracks¿Cvibration between catenary and pantograph. It is dangerous to the equipment in locomotives for the over-voltage and harmonic caused by the arcing. In order to deal with it, the mechanism and process of pantograph arcing has been analyzed. Over-voltage amplitude and duration caused by the arcing have been studied. Meanwhile, harmonic spectrum, current waveform distortion and their influence to traction transformer have been studied. With the above analyzing results, some effective methods to reduce the hazards have been discussed at last.

Pantograph Arc's Energy Characters under Various Load

Sliding electrical contact is the main process for locomotive to carry current in electrical railways. The relative sliding velocity between pantograph and cantenary increases with the speeding up of locomotive, However¿Cthe adhesiveness between pantograph and cantenary decreases. Meanwhile, the contact status of pantograph and catenary get worse. Pantograph arc occurred frequently under these conditions. Pantograph arcing eroded pantograph slider and contact wire seriously. That affected the contacting morphology between pantograph and contact wire severely. The erosion degree is mainly determined by arcing energy. In this paper, the pantograph arcs electrical parameters such as voltage, current and energy were tested under different load by Pantograph-Catenary Arcing Experiment System (PCAES). Relationship between arcs average duration and traction current was analyzed. Influence of load power factor was studied too. Relationship between arc energy and load character was studied at last. It is demonstrated that arcs average duration becomes longer with the increasing of traction current. Arc duration under inductive load is longer than resistive load. Arc energy decreases when load power factor increase.

Over-voltage analyzing for High Speed Railway phase-separation switch

With the development of High Speed Railway (HSR) in China, the demand for increasing HSRs speed become more and more intensively. Switch-ground automatic phase-separation convert is an efficient method to increasing HSRs speed. But for the use of ground converting switch, over-voltage frequently appears at the process of phase-separation. It is harmful to equipments safety. In order to handle it, impacting factors on over-voltage have been studied insight. Relationship between the phase and over-voltage are analyzed. According to the analyzing result, the suitable switching on time for ground converting switch have been proposed.

Simulation system of pantograph arcing

Perfect sliding electrical contact between pantograph and catenary can guarantee the safety and stability of locomotive. Pantograph arcing is one of the main factors of sliding electrical contact performance inelectrified railway system. The main reason of pantograph arcing is the varying gap due to the mechanical vibration between pantograph and catenary. In order to study the pantograph arcing, a novel test apparatus of pantograph arcing has been developed according to the filed application. The apparatus can simulate laterally (zigzag) movement, vertical vibration and the flexible line contact between pantograph contact strip and contact wire. Vibration characteristic of catenary can be simulated by adjusting the contact wire tension. Electrical parameters and morphological features of pantograph arcing were analyzed. It is demonstrated that the features of pantograph arcing is similar to that in field condition.