应用恒电流暂态测量的接地网腐蚀检测方法

Detection method for corrosion of grounding grid using galvanostatic transient measurement

为了实现接地网在不断电、不开挖情况下的腐蚀状态检测,提出应用恒电流暂态测量的接地网腐蚀检测方法。首先,利用传感器模拟接地网在土壤中的腐蚀,并采集其电化学暂态检测信号;其次,采用自适应小波滤波算法滤除检测信号中的噪声信号,该算法将自适应阈值选取方法引入小波滤波中,动态设定各分解层的阈值;最后,应用恒电流暂态测量技术及最小二乘拟合算法获取极化电阻值,并进一步计算其腐蚀速率和年平均腐蚀深度。现场测试结果表明,所提方法测试结果与现场开挖情况相吻合,相较于线性极化法的最小误差仅为1.05%,而最大误差7.61%在可接受范围,其滤波后信号的信噪比大幅度提升,可见该方法检测准确率高、滤波效果较好,可应用于接地网工程实际。

A corrosion detection method using galvanostatic transient measurement of grounding grid is proposed to realize the corrosion state detection under the condition of continuous power and none-excavation.First of all,the sensors are used to simulate the corrosion of grounding grid,and collect the electrochemical transient detection signal.Subsequently,the noise of the detection signal is filtered out via adaptive wavelet filtering algorithm,which integrates the adaptive threshold selection method into the wavelet filtering and dynamically sets the threshold of each decomposition layer.Finally,the polarization resistance is obtained using galvanostatic transient measurement technology and least squares fitting algorithm,thus,the corrosion rate and average corrosion depth can be calculated.Practical field test indicates that the test results of the proposed method are consistent with the on-site excavation.Compared with the linear polarization method,the minimum error only 1.05%,whereas the maximum error of 7.61%is also in the acceptable range.What’s more,the signal-to-noise ratio of the filtered signal is greatly enhanced.In summary,this method has high detection accuracy and good filtering effect,which provides great promise in the practical engineering of grounding grid.