Protection method of traction power supply system for low and medium speed Maglev traffic based on fault traveling wave features

• Published in: IET generation, transmission & distribution transmission & distribution, 2023-12, Vol.17 (23), p.5171-5182
• Main Authors: Yan, Ningning, Wang, Jian, Li, Qingmin
• Format: Article
• Language: English
• Subjects: fault location; power system protection; railway electrification; time‐frequency analysis; transportation
• ISSN: 1751-8687; 1751-8695
• DOI: 10.1049/gtd2.13028

Low and medium speed magnetic levitation traffic with short power supply distance and complex grounding network structure, prone to power supply rail grounding faults. However, the existing fault location methods do not accurately locate the fault point, making it difficult for the protective device to act to cut off the fault. To address the above problems, this paper builds a dynamic simulation model of the low and medium speed magnetic levitation power supply rails to study the distribution characteristics of the fault traveling waves after a ground fault occurs in the power supply rails, and analyses the generation mechanism of the traveling wave spectrum through formula calculation. First, the difference in current between the positive and negative bus bars is analyzed to determine whether a ground fault has occurred. Second, the direction of the current difference between stations is compared to locate the faulty section. Finally, the fault distance is calculated from the frequency difference of the fault voltage at the double‐ended station. Through simulation, the method is validated to be unaffected by fault location, fault transition resistance, noise interference, and is applicable to short circuit faults caused by lightning strikes, and the ranging error always remains within 20 m. The method has strong robustness, can effectively solve the problem of protection misoperation and accurately locate the fault point. It is suitable for low and medium speed magnetic levitation transportation power supply rail ground fault. A dynamic simulation model of the low and medium speed magnetic levitation power supply rails is built to study the distribution characteristics of the fault traveling waves after an earth fault occurs on the power supply rails, and the generation mechanism of the traveling wave spectrum is analysed by means of equation calculations. The difference between the positive and negative bus currents is analysed to locate the fault section, and the fault distance is calculated from the frequency difference of the fault voltage at the double‐ended station. The article method is not affected by fault location, fault transition resistance, noise interference and is applicable to short circuit faults caused by lightning strikes.