Short-Circuit Characteristics Analysis of New Continuous Cable Traction Power Supply System
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摘要:
新型电缆贯通供电系统能够实现长距离输电、减少电分相数目,但两级供电模式将导致该系统结构复杂. 为研究电缆贯通供电系统短路特性,首先,建立单位长度的牵引电缆和接触网-钢轨的二端口网络参数,将各个子网络级联等效成1个二端口网络,进而转化为Ⅱ型电路,实现牵引电缆和接触网-钢轨任意长度的分布参数建模;由于接触网短路后导致机车电压下降,基于车网耦合关系采用迭代计算求解短路电流电压,仿真验证计算方法的准确性. 最后,解析不同短路类型的电气特性,重点分析分布电容对短路电流、电压的影响. 研究结果表明:分布电容会引起短路电流增大,且在不同短路情况下均造成牵引变压器输出电压增加;接触网短路电流由两侧牵引变压器共同提供,距短路点越远提供的电流越少;电缆相间短路对非故障回路机车运行影响最大.
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关键词:
- 新型电缆贯通供电系统 /
- 分布电容 /
- 二端口网络 /
- 接触网 /
- 短路分析
Abstract:New continuous cable traction power supply system (CCTPSS) can achieve long-distance transmission and reduce the number of electric phases. However, the two-stage power supply mode leads to the complex structure of the system. In order to reveal the short-circuit characteristics of CCTPSS, the two-port network parameters of traction cable and catenary-rail of unit length were established. Each sub-network was cascaded and equated with a two-port network, which was then transformed into a Ⅱ-type circuit for modeling the distribution parameters of the traction cable and catenary-rail of any length. The locomotive voltage drops after short circuit of catenary. Therefore, considering the coupling relationship between the train and the network, the short-circuit current and voltage were solved by iterative calculation. The accuracy of the calculation method was validated by simulation. Finally, the electrical characteristics of different short-circuit types were analyzed, with emphasis placed on the influence of distributed capacitance on short-circuit current and voltage. The results show that the distributed capacitance can increase the short-circuit current and, under different short-circuit conditions, the output voltage of traction transformer. The short-circuit current of catenary is jointly provided by traction transformers on both sides, and the farther away from the short-circuit point is, the less current is provided. The cable phase-to-phase short circuit has the greatest impact on the operation of the non-fault-circuit locomotive.
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表 1 3种短路情况短路电流
Table 1. Short-circuit current of three short-circuit conditions
结果与误差 电缆单相接地短路 电缆相间短路 接触网−钢轨短路 模值/A 角度/(°) 模值值/A 角度/(°) 模值/A 角度/(°) 仿真结果 5763.89 −83.54 8849.90 −78.71 8291.06 −79.53 本文计算结果 5771.46 −83.31 8850.04 −78.66 8291.52 −79.48 文献[11]结果 5409.47 −83.22 8542.94 −78.59 7846.05 −78.34 本文误差 7.57 0.23 0.14 0.05 0.46 0.05 文献[11]误差 354.42 0.33 306.96 0.12 445.01 1.19 表 2 回路D1、D2电缆首末端电流
Table 2. Head and end currents of D1- and D2-circuit cables
回路 电缆首端 电缆尾端 $ \mathrm{\mathit{T}}_{\mathrm{T}1} $ 中点 $ \mathit{\mathrm{\mathit{T}}}_{\mathrm{T}2} $ $ \mathrm{\mathit{T}}_{\mathrm{T}1} $ 中点 $ \mathrm{\mathit{T}}_{\mathrm{T}2} $ D1 161.2 406.0 869.00 265.8 523.5 1967 D2 346.0 49.5 30.21 409.0 107.3 58 -
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