轨道交通直流电缆绝缘诊断技术现状及展望

Review and Expectation of Diagnosis Technology on Insulation of DC Cable of Urban Transit

当前直流馈电电缆绝缘诊断主要依靠离线周期性测试和各类保护的动作报警,本文首先分析了现行诊断技术的不足,指出现行诊断技术由于其局限性、被动性已不能满足轨道交通安全运营的需求,应对直流馈电电缆绝缘实施在线监测技术。分析了将交流电缆监测技术应用于直流馈电电缆的可行性。结果表明,交流电缆在线监测技术不能移植于直流馈电电缆,但放电法和直流泄漏电流法可以借鉴参考,有必要进一步开展相关方面的技术研究。

Because of its bad laying environment, the insulation of direct current （DC） feeder cable is a serious hidden trouble factor threatened the operation safety of urban transit. This paper reviews the current diagnosis technology on the insulation of DC cable of urban transit and expects its development. The results of analysis indicate that the implemented diagnosis technology, off-line periodic testing and motion alarming of kinds of protection, didn’t meet the demand of safety operation of urban transit; therefore the new fault predicting technology shall be developed. But at present the on-line monitoring technology is concentrated on AC cable, the relevant research on DC feeder cable is scarcely carried out around the world, so the paper investigates the feasibility of using the on-line monitoring technology on AC cable to detect the DC feeder cable. The results of study show that the on-line monitoring technology on AC cable can not be adopted, but the discharge method and DC leakage current method can be used for reference, and the relevant technology should be investigated in times in order to enhance the safety of power supply of urban transit.