配电网μPMU相量和频率动态测量算法的研究

Research on Dynamic Measurement Algorithm of Phasor and Frequency for Micro PMU in Distribution Network

同步相量测量单元(Phasor Measurement Unit,PMU)的精度决定着电力系统动态安全监控的性能。然而,在频率偏移和瞬态事件的测量中,传统的离散傅里叶变换法由于受静态相量模型的限制,导致计算结果偏差较大。在动态模型的基础上提出一种相量和频率测量的泰勒加权最小二乘算法(Taylor Weighted Least Square,TWLS)。算法分为两步:首先利用插值离散傅里叶变化法(Interpolation Discrete Fourier Transform,IpDFT)对波形的参考频率进行估计;然后在所测频率的基础上利用TWLS对相量和频率进行实时量测。结合同步测量标准IEEE c37.118.1—2011及其修正标准IEEE c37.118.1a—2014对所提算法进行仿真,并与传统算法对比。仿真结果表明:该算法的相量总误差、频率误差、频率变化率误差都能满足标准要求,说明该算法具有良好的动态测量性能和工程应用价值。

The accuracy of synchronous phasor measurement unit(PMU)determines the performance of power system dynamic security monitoring.However,in the measurement of frequency offset and transient events,the traditional discrete Fourier transform(DFT)method is limited by the static phasor model,resulting in large deviation of calculation results.A Taylor weighted least square(TWLS)algorithm for phasor and frequency measurement was proposed based on the dynamic model.The algorithm was divided into two steps.Firstly,the reference frequency of the waveform was estimated by using the interpolation DFT.Then,TWLS was used to measure the phasor and frequency in real time based on the measured frequency.Combined with the synchronous measurement standard IEEE c37.118.1—2011 and its revised standard IEEE c37.118.1a—2014,the proposed algorithm was simulated and compared with the traditional algorithm.The simulation results show that the total vector error,frequency error and frequency change rate error of the algorithm can meet the standard requirements,indicating that the algorithm has good dynamic measurement performance and engineering application prospect.