当跨座式单轨交通直流牵引系统站内列车高压直流回路正极与车体发生短路故障时，会使站内所有列车车体接地继电器GR动作并跳开列车断路器，并会引起全线多处64D接地保护动作并跳开直流馈线断路器，导致直流牵引系统失去电源。为了降低事故影响，需要尽快识别出故障列车并恢复直流牵引系统正常供电。基于跨座式单轨交通直流牵引双边供电系统等值模型，论文首先分析了正极回路与车体发生短路时故障列车和正常列车接地电流和负极受电电流幅值的特征差异，然后提出了一种基于接地电流和负极受电电流幅值比较的故障列车识别方法。当接地电流幅值大于整定值时则启动故障列车识别程序，此时若接地电流幅值大于负极受电电流幅值则列车被判为故障状态，若前者小于等于后者则列车被判为正常状态。最后通过MATLAB仿真和现场测试验证了所提方法的正确性和有效性。该方法简单实用，可靠性高，能为跨座式单轨交通的安全运营提供了有力保障。

When a short-circuit fault occurs between positive pole of high-voltage DC circuit for a train and its carbody inside the station in a straddle seat monorail DC traction system, this causes carbody grounding relay（GR）of all trains inside the station to action and circuit breakers of the train to trip.Meanwhile, this also brings about multiple 64D grounding protections action and trip circuit breaker of the DC feeder.The fault arouses loss of power to the DC traction system. This is necessary to identify the faulty train and restore normal power supplying of the DC traction system as soon as possible in order to reduce the impact of the accident.First, the paper analysed characteristic differences in the amplitude of grounding current and negative receiving electricity current for faulty train and normal train when short-circuit occured between the positive circuit and the carbody based on the equivalence model of DC traction bipolar power supply system for straddle monorail transportation. Second, identification method of faulty train was proposed based on the comparison of grounding current and negative current amplitude. The faulty train identification procedure was activated when the grounding current amplitude was greater than the setting value. In this case the train was judged to be faulty if the magnitude of grounding current was greater than the magnitude of negative receiving electricity current，but it was recognised as a normal state if the former was less than or equal to the latter. Finally, the correctness and effectiveness of the proposed method was verified by MATLAB simulation and field test. The method is simple, practical and highly reliable, which can provide a strong guarantee for the safe operation of straddle-seat monorail traffic.