基于改进递归小波的电力系统频率测量

信号复小波变换的相位谱包含了信号变化的丰富信息,利用电压信号的复小波变换相位信息检测电力系统频率,具有不受电压信号畸变影响、抗噪声能力强、精度高等特点.通过电压信号在特定尺度的改进递归小波变换(IRWT)系数的相位变化周期,可得到电压信号的频率.对理想信号和畸变信号的仿真计算结果验证了该算法具有精度高、速度快、鲁棒性强等特点,市电电压的频率实测结果表明该方法可用于实际电力系统频率的测量.

Power System Frequency Measurement Based on IRWT

As a key indication of power quality, frequency is a significant parameter in power system. Complex wavelets phase spectrum of voltage signal contains plenty information of signal change. Detecting the power system frequency by following phase information of the complex wavelet transform is an efficient way which has the characters of immunity from the influence of voltage distortion, strong resistance of noise and high precision etc. A new method for frequency measurement based on IRWT is presented in this paper. The phase information of the coefficients of the wavelet transform is used to measure the voltage frequency in this method. Simulations and calculation of the ideal signal and distorted signal proved that the method has the advantage of high speed, high accuracy and strong robust. The results of measurement to real voltage show that the method can be used to track the power frequency.