电力系统扰动后稳态频率预测直接法改进

Improvement of Direct Predictive Algorithm of Power System Steady Frequency After Disturbances

在线预测系统扰动后的稳态频率,有利于扰动后系统频率稳定性评估和紧急控制。文中提出一种新的扰动后系统稳态频率预测算法。根据直角坐标潮流二次方程及其泰勒展开式,推导了节点注入功率增量表达式,结合发电机调速器和负荷静态特性建立了稳态频率预测方程。利用扰动后瞬间系统广域量测数据,直接计算系统扰动后的稳态频率。相比已有的频率稳定分析直接法,该算法预测稳态频率的精度更高。最后,利用PSS/E仿真软件,在WSCC9节点系统上对提出的算法进行仿真试验,验证了所提出算法的正确性。计算结果为系统在扰动后的频率稳定性分析和紧急控制提供了重要依据。

On line predicting obtaining power system post disturbances steady frequency is beneficial for frequency stability assessment and emergency control.An algorithm to predict the steady frequency of the power system after disturbances is proposed in this paper.According to the quadratic formulation of load flow equations in rectangular coordinates and its Taylor series expansion,the expression of the increment power injected to the nodes is derived.Combined it with generators governor characteristics and loads static characteristics,the equation to solve steady frequency is set up.The WAMS（wide area measurement system） data right after disturbances is used to calculate the steady frequency.Compared with the existing direct predictive algorithm of steady frequency,the proposed algorithm can provide more accurate predictive result.Finally,a simulation is conducted on a WSCC9-bus power system using PSS/E,which demonstrates the correctness of the proposed algorithm.