动车组MR-139型接地电阻阻抗特性研究

Earthing resistor of MR-139 type used in EMU is of 0.5 ohms at room temperature under DC resistance. It can guarantee the good grounding. However, in the train lifting arch, main breaker action under such circumstances will produce a high frequency voltage signal, the formation of electromagnetic disturbance on emus. Electromagnetic compatibility theory suggests that good grounding is the key to protect the electromagnetic compatibility of electrical and electronic system. Therefore, this paper researches high frequency characteristic of earthing impedance on basis of MR-139; in the view of high-frequency parasitic parameters introduced by resistor mechanical structure, the high frequency equivalent circuit model of the element is built, and simplification of prediction for the design process is proposed. Further measurement method has a simple design, can realize the dynamic characteristics of the online test in the field to earthing impedance.