1、附录 A(原文 ) A Simulation of Arc Generation at AC-DC Neutral Section of Electric Railway Youngsoo Han, Kyuhyoung Choi Abstract-This paper provides an experimental and theoretical analysis of the arc discharges generated between contact wire and pantograph of high speed railway. A video-based arc detect
2、ion device is installed on the KTX train, and arc discharges are measured for a 45.87km track section of high speed railway in Korea. It is measured that the rate of contact loss is 0.3% which is lower than the regulated value of 1.0% for high speed train, and arc discharges induced by 21 small size
3、 contact losses and 6 medium size contact losses occur continuously along the track. The power of arc discharge between contact wire and pantograph is calculated as 9.022.5kW which is approximately one-hundredth of that of the arc discharges generated at the neutral section of contact wire. The resu
4、lts of the measurement and the analysis suppose that a study be followed to suppress arc discharges and contact wire damages for the safe operation of high speed railway. Index Terms Electric railway；arc discharge；contact loss；contact wire； pantograph；neutral section. I.NOMENCLATURE S/S : Sub-Statio
5、n of Electric Railway SP : Sectioning Post SSP : Sub- Sectioning Post AT : Auto-Transformer TF : Trolley Feeder AF : Auto- Transformer Feeder FPW : Fault Protective Wire NW : Neutral Wire NS : Neutral Section CCTV: Closed Circuit Television EMI: Electromagnetic Interference LAN: Local Area Network M
6、CB: Main Circuit Breaker KTX: Korea Train Express II.INTRODUCTION Catenary systems play a important role in supplying electric power without interruption to trains moving fast. The pantographs installed on train collect currents for traction while keeping in contact with the catenary system. Arc dis
7、charges occur between the contact wire and the pantographs, when the pantographs happen to lose contact with the contact wire.Arc discharge also occurs when the train passes through the AC-DC neutral section of the catenary system where electricity is not supplied. These arc discharges give rise to
8、many problems such as spoiling the contact wire and the pantographs,and inducing EMI phenomena,audible noises and other environmental pollutions.Arc discharges generally have large heating power which may spoil the slider of pantograph made of sintered alloy and even breaks the contact wires.Voltage
9、 surges induced by arc discharges may produce EMI problems to the small size environment or mal-operation of electronic devices on the train. The damages caused by arc discharge will be more critical for high speed railway.The faster train moves,the more difficult to keeping in contact with catenary
10、 for pantograph. Moreover, as train speeds up, the train traction currents should be increased,which inevitably give rise to larger arc discharges.This paper provides an experimental and theoretical analysis of the arc discharges generated between the contact wire and the pantograph of high speed ra
11、ilway. A designated arc detection device is installed on the KTX train, and arc discharges are measured for a 45.87km track section of high speed railway.Arc generation frequency, arc current and arc size is measured along the track.A data analysis and an arc power model is suggested too. III. ARC D
12、ISCHARGES BETWEEN CONTACT WIRE AND PANTOGRAPH The power supply system of electric railway consists of S/S and catenary system.S/S converts three phase 154kV electric power to single phase 25kV being suitable for supplying to train.High speed railway adopts AT feeding system which can supply large el
13、ectric power for long distance as shown in Fig. 1. The S/S supplies AC 50kV to AT, and AT supply AC 25kV to train. The converted electric power is supplied to train by way of the catenary system which is composed of a contact wire,a messenger wire and hangers.The main purpose of the catenary system
14、is to supply electric power without interruption to trains moving fast.The pantographs installed on train collect electric power while contacting the contact wire of the catenary system. Fig. 2. Shows the configuration of the catenary system. The pantograph is connected to the contact wire by its li
15、ft force against the contact wire. Contact wires supported by hangers and supporting structures has uneven stiffness points which give rise to contact losses.Moreover,as train speed up,contact loss happens more frequently.Arc discharges occur between the contact wire and the pantographs, when the pa
16、ntographs happen to lose contact with the contact wire. The contact loss phenomena are classified into three groups according to their duration； small size, medium size and large size. Small size contact loss is induced by delicate vibration of pantograph,and continues for several tenths of a second
17、. Medium size contact losses occur when trains pass through the uneven stiff point of the contact wire, and continues for a second and below. Large size contact losses, continuing for several seconds,are induced by jumping movements of pantograph after passing through bracket supporting points of co
18、ntact wire. Contact wires have several neutral sections insulated from other parts of contact wires,in other words dead sections,which divide the sections having different phases and different supply voltages such as AC 25,000V or DC 1,500V. Trains should go into the neutral sections after making no
19、tch-off operation which breaks the train current by MCB, otherwise the train current is interrupted by the neutral section which result in a large arc discharge between the contact wire and the pantograph as shown in Fig. 2.This arc discharge also happens when train go into the voltage-supplied section from the neutral section.
