为实现电压闪变的准确测量,提出了基于S变换的平方检测法电压闪变测量算法。介绍了S变换的基本原理,简化了平方检测法电压闪变的计算过程,给出了基于S变换的平方检测法闪变测量流程。应用S变换对电压闪变信号进行时频分析,由S变换的频域特性曲线求频谱计算闪变值,由S变换的高频频谱幅值和曲线得到电压闪变的起始、结束时刻,仿真结果证明算法的可行性与准确性。在此基础上研制基于虚拟仪器技术的电压闪变测量仪,给出了仪器的构成与主前面板。运行结果表明,仪器操作方便,测量可靠。
To realize high-accuracy measurement of voltage flicker, a kind of voltage flicker measurement method using the square demodulation method based on S-transform was presented. S-transform principles were briefly introduced; the computational process of voltage flicker using the square demodulation method was simplified; and the voltage flicker measurement scheme using the S-transform-based square demodulation method was given. The S-transform is applied for the time-frequency analysis of voltage flicker signals. The frequency domain characteristic given in S-matrix was used for computing the magnitude of the voltage flicker. Based on the high frequency spectrum amplitude, the starting and ending moments of the voltage flicker were estimated. Simulation experiment results verify the feasibility and accuracy of this algorithm. Furthermore, a voltage flickermeter based on virtual instrument technology was developed, and its structure and main front panel were given. The operation results show that the meter has advantages of convenient operation and reliable measurement.