Characteristics of radio frequency interference from pantograph arcing in car of traction stock

In electric railway system, the main radio frequency interference (RFI) effects arise from the high-voltage spark breakdown when the pantograph is raised or lowered and high current arcing during operation. The paper focuses on the characteristics of RFI effects in car of traction stock. Through the experiment in a test line, the pulses of spark breakdown are recorded with high analog bandwidth oscilloscope and analyzed with Fast Fourier Transform (FFT). The analysis shows that the interference spectrum is very wide and the frequencies of main interference energy are below 600 MHz. Furthermore, a time-domain technology is introduced for the measurement of car quality factor (Q) which is used to evaluate resonance effects of car. The technology provides an estimate of average Q by calculating the decay time of the spectrum components of the pulse response. The analysis manifests that the car has little effect on the characteristics of the pulse of spark break.