Research On The High Frequency Characteristics Of EMU Grounding Resistance And Its Characteristics Under Surge Strike

Compared with ordinary electric locomotives, High-speed Electric Multiple Units takes multiple advantages of safe, comfortable, short interval and on-time rate. The development of High-speed rail promotes the economic, transportation, energy and a series of related industries. However, there are some differences between High-speed and traditional railway system. Our country started to research High-speed rail late, so there are many electrification problems need to be solved. Nowadays, CRH2and its follow-up CRH380A(L) equipped with MR-139ground resistance. It introduced from Japan Kawasaki Heavy Industries. Until now, the ground resistance has rarely been studied. This paper attempts to give MR-139ground resistance a comprehensive research in various aspects,Firstly, we introduced the grounding system of CRH2EMUs, analyzed the importance of grounding resistance. Then we constructed a model of this ground resistance. According to its distributed inductance, distributed capacitance in the high-frequency condition, we simplified the model and clarified the purpose of testing.Then, we introduced the basic type of bridge method and the principle of various bridges. We used the bridge method to measure the inductance and use the data to estimate the impedance in various frequencies. What’s more, we pointed out the lack of impact current method and proposed the method of U/I on single frequency. We described the advantage of it in detail and test it in lab and vehicle. By the way, we test the temperature characteristics of ground resistance.Next, we did the lighting strike test of ground resistance. We introduced the basic concepts of lightning and its parameters. Then we introduced the impulse grounding resistance and the over voltage causes and solutions. Next we analyzed the spectrum of lighting, clarified the range of its energy distribution. We did the surge test according to the standard surge waveform and calculated the impulse grounding impedance of it. Then we did the test of repeated stuck by surge.Finally we make a comprehensive conclusion of the characteristics of MR-139ground resistance, and proposed following research suggestions.