Research And Application Of Wideband Modeling And Time Domain Calculational Method In High-speed Railway Traction Power Supply System

Traction power supply system and railway cable continuous power line are the important infrastructures and play a decisive role of the high-speed railway system. The operating data indicates that the lightning failure is one of the important factors that affect the reliability of the power supply system of the high-speed railway. Supported by the Eleventh Five-Year Plan for National Science and Technology (Grant No.2009BAG12A09) and the National Natural Science Foundation of China (Grant No.51177048), the wideband modeling method and the time domain calculational method of the catenary multi-conductor system, the integrated grounding system and the lOkV railway cable continuous power line in high-speed railway are studied, the indirect and direct lightning overvoltages and the flash-over rate are calculated. The main innovative achievements are presented as follows:1. The improved Delay Extraction-Based Passive Compact Transmission Line (DEPACT) macromodeling algorithm for calculating the induced voltages of the overhead transmission line is proposed. Compared with the existing methods, the segmentation number of the transmission lines can be effectively reduced and the operating efficiency can be raised. Furthermore, because the improved model can be solved in the phase domain instead of in the modal domain, it can be embedded into the circuit simulation software, which provides a conveninet and efficient way for calculating the lightning induced ovrevoltages of the overhead transmission lines.2. Based on the partial element equivalent circuit (PEEC) method, the integrated grounding system of the rail transit viaduct is modeled and the time domain calculational method is also derived. Combined with the multi-conductor transmission lines model of the catenary, the indirect and direct lightning overvoltages are calculated, the flash-over rates of the catenary are evaluated, and an effective lightning protection measure is put forward.3. An efficient time domain finite element method for the transient response of MTLs with frequency-dependent parameters excited by an external electromagnetic field is presented and a value-delivery table to form the coefficient matrices is generalized. The stability condition of this method is also studied and the conclusion is archived that the method proposed in this paper is unconditionally stable for any temporal step. The method is verified to be correct by comparing the results with the existing method.4. Combined with the fractional identification method and numeric solution to the fractional order differential equation, a general wideband modeling method is proposed. Comparing with the existing wideband modeling method, the orders of the model can be reduced effectively. Considering the indispensability of the passivity verification of a system for the transient simulation, a passivity verification method for the fractional order state-space system is studied and a practical criterion is proposed in this paper.5. A novel wideband model of the cable is presented based on the fractional order wideband modeling method and the model is verified by comparing with the results of the existing method. The indirect and the direct lightning overvolages of the lOkV railway cable continuous power line are computed and analyzed, and the lightning protection measures are put forward.