非同步采样情况下有功电能时域计量新方法

在非同步采样情况下,使用FFT分析电网信号时,会出现频谱泄漏现象,从而降低有功电能的计算精度。为保证基波和谐波有功电能的测算精度,提出时域分析基波和谐波参数的计算方法。该方法通过对基波信号进行积分来获取基波参数,在此基础上,建立基于傅里叶级数的电压和电流信号模型,并使用递推最小二乘法对采集的电压和电流信号进行模型辨识来获取基波和谐波参数,从而实现基波和谐波有功电能的测算。数值仿真结果表明,该方法不仅具有较高的有功电能测算精度,而且只需要3个额定工频周期窗口的采集数据即可获得基波和谐波的最优参数,进而可以预先获得10个额定工频周期窗口的有功电能,因而是一种有效的有功电能计量方法。

A new time domain measurement method of active electric energy under non-synchronous sampling

If a power grid signal is analyzed by the FFT algorithm in the case of non-synchronous sampling,it will cause the spectral leakage,and calculation precision reduction of active electric energy.In order to ensure calculation accuracy of fundamental and barmonic active electric energy,a time-domain calculation method for fundamental and harmonic parameters is proposed.Fundamental parameters are calculated by the integral of fundamental signal On this basis,voltage and current signal models are established based on F ourier series.Fundamental and their harmonic parameters are then identified by using the RLS algorithm to match the sample data of voltage and current signals.As a result,the measured values of fundamental and harmonic active electric energy are obtained.The numerical simula-tion results show that the proposed method has high measurement accuracy of active electric energy.The optimal parameters of fundamental and harmonic are obtained by the sample data in only three rated cycle windows in working frequency.In this way,the active electric energy of the ten rated operating frequency period can be obtained in advance.Hence,it is an ffective measurement method of active electrice energy.