摘要
非同步采样是造成频谱泄漏和影响谐波测量精度的重要因素。为提高非同步采样的测量精度,提出一种在固定采样频率条件下的谐波测量算法。该算法基于DFT的梯形积分原理,在系统频率发生偏移时将一个周期内的采样点数分为整数点和分数点,利用分数点的积分结果去修正谐波测量结果。为求取分数点对应的采样值,采用了线性插值算法。所提出的算法无需硬件频率跟踪电路,数据窗长度仅为一个周波,特别适合于保护、测控、故障录波等多功能一体化智能电子装置。仿真计算及实际装置运行均表明,当系统频率在45～55Hz之间变化时,此修正算法均可以有效地提高基波和谐波的测量精度。
Asynchronous sampling is one of the main factors that cause spectrum leakage and harmonic measurement inaccuracy.In order to improve the measurement accuracy of the asynchronous sampling,this paper proposes a harmonics measurement algorithm assuming the fixed sampling rate.The proposed algorithm,which is based on the DFT trapezoidal integration principle,divides the sampling points in a cycle into integer points and fraction points.The integration of the fraction points is then used to compensate for the measurement result.The linear interpolation method is adopted to calculate the sampling value of the fraction point.When using the proposed algorithm,a frequency-tacking circuit is needless,and the length of the data window is just one fundamental cycle.As a result,the algorithm is most suitable for the multi-functional IEDs which integrate such functions as protection,measurement, control and disturbance recording.Both the simulation results and the practical operation of the device demonstrate that the proposed algorithm can improve the accuracy of the harmonic measurement effectively when the system frequency drifts between 45 Hz and 50 Hz.
出处
《电力系统保护与控制》
EI
CSCD
北大核心
2010年第19期65-69,共5页
Power System Protection and Control
