变换群

Comparing with existing solutions, new method can utilize generators' speed signal measured by wide area measurement systems directly and detailed model and parameter of power system components were not needed. After sphering measurement-data, ICA with maximal negentropy criterion was carried out to obtain feature matrix. By this means high-dimension data of multi-machine perturbed trajectories were reduced to lower dimensions, and coherent generator groups were identified by pattern recognition consequently. Simulation results of 36-bus system with 8-generator and planning northwest China 750 kV power grid show that noise signals and bad data can be eliminated. This method is accurate in identifying coherent generator groups.

与现有方法相比，这种方法不需要获得系统元件模型和参数，而是直接球化广域测量系统(wide area measurement systems，WAMS)提供的发电机电角速度信号，再利用最大负熵准则进行独立分量分析得到特征矩阵，将高维数的多机受扰轨迹数据变换到低维空间，通过模式识别得到分群结果。8机36节点系统和西北750 kV电网规划系统算例表明，该方法能有效消除噪音和坏数据的影响，准确识别出同调机群。

They weren't aggressive, but I yelled and threw a rock in their direction to get them off the trail and away from me, just in case.

他们没有侵略性，但我大喊，并在他们的方向扔石头让他们过的线索，远离我，以防万一。

In slot 2 in your bag put wrapping paper, quantity does not matter in this case.

在你的书包里槽2把包装纸、数量无关紧要。