DPSD在PT二次侧检测中的应用

Application of DPSD algorithm in the detection of PT secondary side

随着电能计量准确性要求的不断提高,以及“注入信号法”在故障选线及电容电流测量中的广泛应用,PT二次侧信号的准确检测就显得尤为重要。在PT二次侧提取信号时,传统的检测方法检测精度不高,很难满足实际应用要求。因此,提出将数字相敏检波(DPSD)应用到PT二次侧的信号检测中,该方法的优点是不仅能检测信号幅值大小,同时能检测信号的相位。此外,DPSD检测精度较高,特别适用于低信噪比(SNR)的检测场合。设计DPSD检测算法,在MATLAB/SIMULINK环境下建立仿真模型,验证在PT二次侧检测低SNR信号的效果,检测结果证明DPSD有效地抑制了电网中谐波信号和强噪声,并能准确地将感兴趣信号提取出来。

With the increasing demand for the accuracy of electrical energy measurement and the extensive application of injection signal method in fault line selection and measuring capacitive current,the accurate detection of the secondary side signal of the PT is particularly important.The precision of the traditional detection method is sub-standard when extracting signals on the secondary side of PT,so it is difficult to meet the practical application requirements.Therefore,the digital phase sensitive detection(DPSD)algorithm is applied to the signal detection of the secondary side of the PT,the advantage of this method is not only able to detect the signal amplitude of the signal,but also able to detect the phase of the signal.In addition,the DPSD algorithm is especially suitable for low SNR detection occasions with high detection precision.The DPSD algorithm was designed and the simulation model was set up in the MATLAB/SIMULINK to verify the effect of detecting the low SNR signal at the secondary side of PT.The detection results prove that the DPSD algorithm effectively inhibited the harmonic signals and strong noise in the power grid,and accurately extract the useful signal.