考虑频率偏差的动态同步相量估计器

Dynamic Synchrophasor Estimator Considering Frequency Deviation

电力系统负载变化和次同步谐振等诸多原因均会导致电力系统频率偏离标称频率,IEEE标准C37.118.1和最新修订后的C37.118.1a中规定的电力系统最大频率偏差可达5Hz,较大的频率偏差会导致基于泰勒傅里叶的同步相量测量算法产生严重误差。该文提出一种考虑频率偏差的动态同步相量估计器,该估计器在标称频率的两侧以固定的频率间隔生成多个离散频率,基于这些频率离线生成相应的动态滤波器,并将滤波器系数保存到存储器以便在线运行时查表使用。算法运行时,利用泰勒傅里叶的频率估计功能对信号频率进行预测,根据预测频率选择与之最接近的离散频率,通过查表法找到相应的滤波器对输入信号进行分析,实现了较大频偏时同步相量的精确测量。最后,通过仿真和实际信号数据对所提出的估计器进行了测试,测试结果表明,该估计器能够在较大频偏时实现对同步相量、频率和频率变化率的精确测量。

Many reasons,such as power system load changes,sub-synchronous resonance and so on,will cause the system frequency to deviate from the nominal frequency of the system.The maximum frequency deviation specified in IEEE standard C37.118.1 and the latest revised C37.118.1a can reach 5Hz and larger frequency deviation will cause Taylor-Fourier to produce serious analysis errors.This paper proposed a dynamic synchronous phasor estimator considering frequency deviation.In this estimator,multiple discrete frequencies were generated at fixed frequency intervals on both sides of the nominal frequency,and then the corresponding dynamic filters were generated offline based on these frequencies,and the filter coefficients were saved to the memory for use during online operation.When the algorithm was running,Taylor-Fourier was used as a frequency detector to predict the signal frequency,and the closest discrete frequency was selected according to the predicted frequency.Then,the corresponding filter was found through the lookup table method to analyze the input signal and accurate measurement of synchronous phasor was realized under the frequency deviation case.Finally,the proposed estimator was tested through simulation and actual signal data.Test results show that the estimator can estimate the synchrophasor,frequency and rate of change of frequency under frequency deviation conditions.