四分之三基波周期最小二乘相量估计算法

Synchrophasor Estimation Using Three-Quarter Fundamental Period Least Squares

同步相量估计算法对同步相量测量单元(phasor measurement unit,PMU)的性能有重要影响,如何获得准确、实时性好、具有良好动态性能的相量估计算法值得研究。为此,提出四分之三基波周期最小二乘(three-quarter fundamental period least squares,TQLS)相量估计算法。TQLS法的估计周期为四分之三基波周期,即对该时间窗内的信号进行采样,根据公式推导的结论,可以得到采样结果与基波相量之间的关系。利用最小二乘法,可以由采样结果估计出相量。在整个估计过程中没有泰勒级数展开。理论分析表明,所提TQLS算法可以准确估计基波相量,同时,该算法在基频附近频率响应的幅值平坦,可以准确估计动态相量。仿真结果分别从频域和时域角度验证了TQLS算法的有效性,并且仿真结果显示TQLS算法的计算量与傅里叶变换法相当。

Synchrophasor estimation algorithm greatly influences the performance of phasor measurement unit （PMU）, so how to obtain the phasor estimation algorithm with high accuracy, good realtime performance and satisfied dynamic property is worthy to be researched. For this reason, a synchrophasor estimation algorithm based on three-quarter fundamental period least squares （TQLS） is proposed. The estimation period of TQLS is three-quarter fundamental period, namely the signals within this time-window are sampled, and according to the conclusion from formula derivation the relation between the sampled results and fundamental phasor can be attained. Utilizing least square method the phasor can be estimated by sampled results. During the whole estimation process the Tailor series expansion is not used. Theoretical analysis shows that using the proposed TQLS algorithm the fundamental phasor can be accurately estimated, meanwhile the amplitude of the frequency response of this algorithm near the fundamental frequency is fiat, thus the dynamic phasor can be accurately estimated. The effectiveness of TQLS algorithm is validated by time- and frequency-domain simulation results, besides, simulation results show that the calculation amount of TQLS algorithm is equivalent to that of Fourier transformation.