非整周期采样条件下有功电能计量的新算法

New active electric energy measurement algorithm under non-integer-period sampling

非整周期采样条件下,应用FFT算法对信号进行分析时,会产生频谱泄漏,从而使有功电能的计量产生误差。在明确基波有功电能和谐波有功电能的定义,并证明负载所消耗的总有功电能与电压电流信号的频谱之间存在一定关系基础上,提出一种基于谐波子组加窗FFT的有功电能计量新算法。类似于IEC标准中谐波子组的分组方法,对加窗信号的频谱进行分组,并基于加窗前后信号总有功电能保持不变而得到电能恢复系数;同时,应用谐波子组内谱线的参数信息测算出基波有功电能和谐波有功电能值。数值仿真分析和实际应用验证发现,若该新算法配合以Hanning窗进行信号处理,其在测算基波有功电能和谐波有功电能时均具有较高的准确度。

If a signal is analyzed by using FFT algorithm under non-integer-period sampling condition,it will cause spectral leakage,and cause measurement error of active electric energy. After defining fundamental active electric energy and harmonic active electric energy,and proving that there is a certain relationship between the total electric energy consumed by loads and the spectrum of voltage and current signals,the harmonic subgroup windowed FFT algorithm is proposed. Firstly,it groups the spectrum bins of the windowed signal using the harmonic subgroup grouping method in IEC standard. Then,the electric energy recovery coefficient is calculated based on the rule that the total active electric energy remains unchanged after the signals is windowed. Lastly,fundamental electric active energy and harmonic electric active energy is obtained using the coefficient and the harmonic subgroup bins ＇parameters. Numerical simulation analysis and actual evaluation show that the new algorithm uses Hanning window to process the signals,it can achieve higher accuracy to calculate fundamental electric active energy and harmonic electric active energy.