In order to ensure personal safety, overvoltage protection devices (OVPD) are usually installed in stations and depots of operating lines. However, the overvoltage generated during the reset of the rail potential limiting device may cause the OVPD section II to act or even lock, resulting in the rail potential limiting device short circuiting the ground and rail, becoming a path for stray current leakage. With the continuous increase of urban rail operation mileage, stray currents have caused serious problems such as DC bias in the surrounding power system and corrosion damage to the urban pipeline network, which have seriously threatened the safe operation of the power system and oil and gas system. This paper proposes a suppression method for the overvoltage caused by the misoperation of the rail potential limiting device caused by abnormal rail potential, which exacerbates the leakage of stray currents in urban rail transit. The method involves constructing a simulation model of the overvoltage generated by the OVPD opening of the rail potential limiting device, constructing an arc experimental platform using N1250 contactors, and conducting grid mounted testing on actual lines. The results show that after using the overvoltage suppression method proposed in this article, the peak operating overvoltage generated by the opening of the rail potential limiting device is significantly reduced, reducing the possibility of OVPD misoperation and stray current leakage.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |