基于三角基函数分解的高精度介损角测量方法

为精确测量介损角,克服数字化测量时存在的非同步采样、基波频率波动、谐波变化等因素影响,提出并建立基于三角基函数分解的介损角测量模型,将电力谐波各参数作为未知量,基于最小二乘原理对采样数据进行最速下降迭代求解,准确提取基波电压、电流相位,进而得出介损角,排除直流和谐波分量干扰。从理论上证明该算法的收敛性,针对基波频率波动、介损角真值改变、谐波含量变化、白噪声影响等影响进行仿真实验,结果表明该测量方法使用极少采样点与较低采样率,即可获得较高的测量准确度,测量速度快。设计的基于数据采集卡与虚拟仪器技术的高压电容型设备绝缘在线监测系统,验证了该方法的可行性与有效性。

High accurate dielectric loss angle measurement method base on triangle basis function decomposition

To achieve an accurate dielectric loss angle (DLA), non synchronization sampling, fundamental frequency fluctuation and changing of harmonic component should be overcome during the process of digital measurement. Therefore, a measurement model of dielectric loss angle based on the decomposition of triangle basis function (TBF) and least square (LS) is presented. The model takes the power frequency as an unknown parameter and creates a steepest descent iterating model based on the least square. Through it the accurate extraction of fundamental wave phase voltage and current phase can be obtained, and then the dielectric loss angle can be obtained without the interference of direct bias and harmonic component. The convergence of the method is proved theoretically through the simulations used in fundamental frequency fluctuation, changing of harmonic component, real value of dielectric loss angle variance and white noise problems. High accuracy and fast measurement speed can be achieved with less sampling data and lower sampling rate in this method. The online monitoring system applying DAQ and virtual instrument technology also verifies the effectiveness and practicability of the method.