电气火灾监控探测器剩余电流分析方法

The analysis of residual current based on fast fourier transforms

根据电梯启动时产生的剩余电流干扰信号,分析剩余电流式电气火灾监控探测器产生误报警的原因。通过对电梯静止、上升、下降过程中干扰信号的频谱分析,提出电梯在不同运行状态的干扰信号的频率特性。介绍采用快速傅里叶变换分析电梯配电线路中剩余电流的方法。实验结果表明,电梯运行时产生的剩余电流干扰信号的频率主要分布在3 000Hz以上,电梯静止时3 700Hz频率的干扰信号能量最大,电梯上升或下降时4 500 Hz频率的干扰信号能量最大;通过快速傅里叶变换分析电梯配电线路的剩余电流的频谱特性,提取频率从48Hz到52Hz信号的幅值,可作为配电线路是否产生漏电的判据。

According to the disturbing signal caused by running elevator, the reasons of residual current electrical fire monitoring detectors false alarm was analyzed. The spectrum charac teristics of the disturbing signal were analyzed, and the fre quence characteristics during the elevator running up, running clown and stop were stated. The residual current analysis method in elevator distribution lines by Fast Fourier Transforms was introduced. Experimental results indicated that the frequence of the disturbing signal is mostly more than 3 000 Hz. The high est energy of the disturbing signal＇s frequence focuses on 4 500 Hz when elevator is running up or running down. The highest energy of the disturbing signal＇s frequence focuses on 3 700 Hz when elevator stops. Extracting the amplitude of signal whose frequence is from 48 Hz to 52 Hz by analyzing the spectrurn of the residual current with Fast Fourier Transforms can tell whether the leakage fault happen.