基于AT供电方式下380B型高速动车组保护接地电流分布研究

Research of Protective Grounding Current Distribution of 380B EMU Based on AT Power Supply Mode

目前中国高速动车组的接地方式为分散式,该接地方式形成的回路电流对动车的安全运行构成潜在威胁。在Simulink平台上搭建了AT供电模式下380B型动车组的车-网模型,并结合实验测取动车组保护电流的实际数据分析其变化规律。研究发现:吸上线使得保护电流的大小及相位呈周期约为20s的循环变化,1、8车的1轴经过吸上线时保护电流幅值最大为170A。整车回流的流向与列车位于吸上线区间位置有关,整体规律为从远离吸上线的保护接地流进车体,并从靠近吸上线侧的1或8车1轴流出。另外,在原有模型的1、8车加上0.1Ω的接地电阻,各个保护电流的大小能够得到有效抑制。以上结论为设计更优良的接地方案提供了理论基础。

At present,EMUs in China adopt dispersive grounding system,which produces loop current among grounding points and forms a potential threat to the safe operation of the EMU. In this paper,a test of protective current waveforms was carried out and a model of train and Overhead Contact System of 380B EMU based on the AT power supply mode was established by Simulink software to study the distribution of protective current. The results show that the amplitude and phase of protective current change in a cycle of about 20 s due to the influence of mid-point connections. The maximum amplitude of protective current is 170 A when the No.1 shafts of No.1 and No.8 cars pass through the mid-point connections. The phase of protective current is related to the position of the train in the mid-point connection section. The holistic regularity is that the current flows into the car body from the protective grounding that is far away from the mid-point connections and flows out from the No.1 shaft of No.1 or No.8 car near the mid-point connections. In addition,adding a grounding resistance of 0.1 Ω on the No.1 and No.8 cars can effectively reduce the amplitude of all the protective current. The above conclusions could provide a theoretical basis for designing better grounding schemes.