基于能量时空分布熵的低频振荡类型判别方法

Discrimination Method for Low-frequency Oscillation Type Based on Entropy of Energy Distribution in Space and Time

电力系统发生低频振荡时,准确判断振荡类型对确定振荡起因和采取抑制措施至关重要。将低频振荡细分为局部振荡、区间振荡和局部—区间耦合振荡,并从熵的基本原理出发,结合不同类型低频振荡的振荡能量时空分布特性,提出基于能量分布熵的低频振荡类型判别依据。首先利用Prony分解提取主导振荡模式的电气量数据,计算各机组振荡能量并且得到振荡能量空间分布熵和标幺化标准差分类指标,然后通过增加滑动窗的方式动态反映振荡能量随时间的变化态势,对结果进行曲线拟合显示不同类型振荡能量时空分布规律,利用熵差综合分类判据对低频振荡类型加以区分。通过华北电网不同类型低频振荡仿真计算,验证了所述方法的有效性。

When the low-frequency oscillation occurs, the accurate oscillation type discrimination is crucial to determine the oscillation causes and take the reasonable suppression measures. This paper subdivides the low-frequency oscillation into local oscillation, interval oscillation and local-interval coupled oscillation. Based on the basic principle of entropy and the oscillation energy temporal and spatial distribution characteristics of different types of low frequency oscillation, the discrimination criteria based on the energy distribution entropy is proposed. The electrical quantity data of dominant oscillation mode is extracted by Prony decomposition firstly, and the criteria of spatial distribution entropy and normalized standard deviation can be obtained by calculating the unit oscillation energy. Then, the trend of oscillation energy is reflected by adding the sliding windows and the temporal and spatial distribution characteristics are manifested by curve fitting. Finally, different types of low frequency oscillations are distinguished by the entropy-deviation classification criterion. Simulation results of different type low frequency oscillations in North China power grid demonstrate the validation of this method.