提出了一种基于三次样条插值和时标变换的智能变电站保护数据重采样算法。当电力系统频率偏移时,重采样得到傅里叶算法一个数据窗内的整周期采样数据,减小了频谱泄漏误差。过程层数据采样率与保护算法不匹配时,实现了采样率向保护算法采样率的转换。算法可减小过程总线采样值传输产生的延迟和丢包对保护带来的误差。MATLAB数值仿真结果表明,重采样算法在互感器合并单元采样数据与保护算法不匹配情况下可实现采样数据与保护算法的“无缝连接”。利用MATLAB/Simulink建立电力系统故障模型,仿真结果验证了算法应用于实际电力系统保护的有效性和适用性。
A re-sampling algorithm for smart substation protection data based on cubic spline interpolation value and time scale transformation is proposed in the paper. When the power system frequency shifts from nominal 50 Hz, the full-cycle sampled values in a data window of the Fourier algorithm are obtained by re-sampling so as to reduce the spectrum leakage error. The proposed algorithm also realizes sampling rate conversion from the fixed sampling rate of process level data to the sampling rate required by protection algorithms. The proposed re-sampling algorithm can efficiently reduce errors caused by lost or delayed sampled value on process bus in transmission. Simulation results based on MATLAB show that, the proposed re-sampling algorithm can realize "seamless connection" of sampled data with protection algorithms when merging units sampling data of transformers is mismatched to the protection algorithms. And simulation results of a power system fault model built by MATLAB/Simulink validate the effectiveness of the proposed algorithm applied to the protection of actual power systems.