大功率低压IT系统绝缘监测技术研究

摘要

研究了大功率低压IT系统多并联电缆供电的特点，分析了其绝缘监测的难点，提出了一种基于外加信号的综合绝缘故障监测方法。该方法可实时监测系统内相线及中性线的绝缘电阻值，当绝缘电阻值低于设定阈值(通常为50 kΩ)时可报警；同时也可以对多并联电缆进行选线，指示故障相。试验结果表明，该方法具有较高的可靠性和测量精度。%This paper studied the characteristics of high-power low-voltage IT system with multi-parallel power cables, as well as the difficulties of insulation monitoring. This paper presented a comprehensive insulation monitoring method based on additional sig-nal. The method could monitor the insulation resistance of system’s phase wire and neutral wire in real time, giving an alarm once the insulation resistance decreased to the threshold (normally 50 kΩ). In addition, this method could select the fault circuit from multi-parallel power cables, indicating the fault phase. Experiments show that the method has high security and precision.