地铁列车轴箱轴承电流测试与接地方式优化

Current Test and Grounding Mode Optimization of Axle Box Bearing for Metro Train

在分析轴箱轴承电流产生的基础上,对地铁列车直接接地和串联电阻接地2种方式下的轴承电流分布进行测试,其中,直接接地方式下车体与转向架、转向架与轴端直接通过保护接地线连接,串联电阻接地方式下车体与转向架直接通过保护接地线连接,车体与轴端保护接地线间串联50 mΩ的电阻。对实测数据的分析发现,2种接地方式下全车的轴承电流与牵引电流均呈线性正相关,且串联电阻接地方式下二者的相关性更明显,但牵引电流并非影响轴承电流的唯一因素,串联电阻接地方式对轴承电流的抑制效果不佳。由此,提出动车车体经串联电阻接地、拖车车体直接接地的新型接地方式,在建立并验证轴承电流仿真模型准确性的基础上,对新型接地方式的有效性进行验证。结果表明:与原有2种接地方式相比,新型接地方式在大幅降低动车轴承电流的同时,不会升高拖车轴承电流;比较直接接地方式,新型接地方式下全车轴承电流均有明显的下降,抑制比例达30%以上。

Based on the analysis of axle box bearing current source,the bearing current distribution of metro train under direct grounding mode and series resistance grounding mode was tested.In the direct grounding mode,the car body and bogie,the bogie and the axle end were directly connected by the protective grounding wire.In the series resistance grounding mode,the car body and bogie were directly connected by the protective grounding wire,the car body and axle end were connected by the protective grounding wire in series with a resistance of 50 mΩ.Through the analysis of the measured data,it was found that the bearing current and traction current of the whole vehicle were linearly positively correlated under the two grounding modes,and the correlation between them was more obvious under the series resistance grounding mode.However,the traction current was not the only factor affecting the bearing current,and the suppression effect of the series resistance grounding mode on the bearing current was not good.Therefore,a new type of grounding mode was proposed,which was the series resistance grounding of EMU body and the direct grounding mode of trailer body.On the basis of establishing and verifying the accuracy of the bearing current simulation model,the validity of the new grounding method was verified.Results show that:compared with the two original grounding modes,the new grounding mode can greatly reduce the motor car bearing current,but it will not increase the trailer bearing current.Compared with the direct grounding mode,the bearing current of the whole vehicle under the new grounding mode is significantly reduced,and the inhibition ratio is more than 30%.