新型电缆贯通供电系统载流机制

新型电缆贯通供电系统能够取消电分相环节，延长供电距离，并有效治理电气化铁路中的电能质量问题. 但电缆牵引网（cable traction network， CTN）包含不同的电压等级，基波电流要首先经过牵引网的各个环节，最终汇聚到列车负载；而列车发射的谐波电流要经过两级渗透，最终返送到公用电网. 为研究电缆贯通供电系统的载流机制，针对CTN的特殊拓扑结构，根据双口网络分析方法，建立了车网耦合系统等值电路；分析了CTN中的电流传输规律；利用仿真模型，研究了CTN中的谐波电流分布与中心变电所（main substation， MSS）的谐波电流含量. 研究结果表明:当系统内有8个短回路时，单车工况下，基波电流主要在列车所在的单侧供电区间传输；机车电流与MSS电流之比小于4 （牵引变压器变比）；MSS谐波电流含量较列车处最多降低了43.5%. 

Current-Carrying Mechanism of New Continuous Cable Traction Power Supply System

Continuous cable traction power supply system is free of electrical phase separation and extend power supply distance, dealing with power quality problems effectively. However, cable traction network (CTN) contains different voltage levels, and the fundamental frequency current flows every CTN link before being used by trains. Moreover, the harmonic current transmitted from trains needs to penetrate in two voltage levels before feeding back to utility grid. In order to study current-carrying mechanism in novel continuous cable TPSS, starting from the special topology of CTN, the equivalent circuit of train-CTN coupling system is established according to dual-port network analysis method. Then current transmission rules in CTN are analyzed. Combined with simulation model, the harmonic current distribution in CTN and harmonic current content of main substation (MSS) are studied. When the new system contains eight short sections for one train, the fundamental frequency current is mainly transmitted by the single-sided CTN where the train locates, and the current ratio between load and MSS is less than four (traction transformer ratio). The harmonic current content of MSS decreases by 43.5% compared with harmonic current content at train.