一种面向剩余电流保护装置的触电阻抗建模方法

摘要

In order to solve the refusing action and maloperation problem of electric shock of living organisms of Residual Current operated protective Device (RCD) in low voltage distribution network,an electric shock impedance modeling method is proposed in this paper.Through building up the test bed of electric shock of living organisms,electric shock voltage and current data are collected.After filtering the original electric shock signal,the electric shock voltage and current signal are transformed from time domain to frequency domain by using Fast Fourier Transform.Electric shock voltage and current power frequency component can be extracted.The total electric impedance amplitude and phase values of the living organisms are based on Ohm law.Based on the group of 30 electric shock impedance values,the data fitting method is utilized to calculate the value of the living organism electric impedance amplitude and phase.Furthermore,the skin resistance and capacitance of the living organisms can be got based on H.Freiberger equivalent circuit.Then,the digital simulation model is built up in MATLAB by using Simulink.Through validating of the impedance modeling,the results show that the model can reproduce the transient process of electric shock organism well.The proposed electric shock impedance model can be utilized as operation criterion of RCD.The results also indicate that the proposed modeling method can improve the operation of RCD with better accuracy and reliability.%针对低压电网剩余电流保护装置在生物体触电方面存在拒动、误动的问题,本文提出了一种生物体触电建模方法.本方法通过搭建生物体触电物理实验平台,获取各种场景下生物体触电电压、电流数据,对原始触电信号进行滤波预处理后,通过傅里叶变换将触电电压、电流信号由时域转换到频域,进而提取电压、电流工频分量,再由欧姆定律计算出生物体的触电总阻抗幅值及相角值.对于求取到的30组触电阻抗数值,采用数据拟合的方法计算出最优的生物体触电总阻抗幅值及相角值.依据弗莱贝尔格等值电路获得动物的皮肤电阻和皮肤电容,获得生物体触电阻抗模型.通过MATLAB软件搭建生物体触电物理实验平台的数字仿真模型,对求取的生物体触电阻抗模型进行仿真验证,仿真结果表明本文所提模型可以较好地复现生物体触电的暂态过程.通过本研究搭建的生物体触电模型,可提取生物体触电信息用于剩余电流保护装置的动作判据,进而有效提高剩余电流保护装置动作的可靠性和准确性.