考虑频率波动的孤岛微电网在线三相概率潮流计算方法

为了量化短期源荷功率扰动对频率波动的影响并保证模拟精度,从短期概率潮流问题出发,采用预测分量和随机预测误差分量分别表示风电和负荷的实时扰动功率,同时用一次调频实现扰动功率中随机预测误差分量的平衡,用基于超前控制方式的二次调频实现系统当前功率缺额和扰动功率预测分量的平衡,从而实现了对源荷功率扰动影响的准确量化评估。同时,提出的模型考虑了微电源的三相电压、电流对称控制特性以及可控微电源与负荷的静态频率电压调节特性,精确模拟了孤岛微电网的调频过程以及微电源的三相潮流控制特性,因而大幅提高了三相潮流与频率波动的仿真精度。采用三点估计法实现所建模型的概率评估,并通过IEEE 33节点修正系统的仿真分析验证了所提方法的有效性。

Online three-phase probabilistic power flow calculation method for islanded microgrid considering frequency fluctuation

In order to quantify the impact of short-term source-load power disturbance on frequency fluctuation and guarantee the simulation accuracy, a three-phase probabilistic power flow model of microgrid is developed. In this model, the prediction component and random prediction error component are employed to represent the disturbance of wind power and load demands respectively. At the same time, the primary frequency regulation is utilized to balance the random prediction error. The secondary frequency regulation based on advanced control mode is used to balance current power shortage and the prediction component of disturbance power. In addition, the proposed model considers the symmetrical control characteristics of three-phase voltage and current of micro sources, and the static frequency voltage regulation characteristics of controllable micro sources and loads are considered. Furthermore, the model can accurately simulate the frequency adjustment process of the islanded microgrid and the three-phase power flow control characteristics of the micro sources. As a result, the simulation accuracy of three-phase power flow and frequency fluctuation can be efficiently improved. Three-point estimation method is applied to provide the probabilistic evaluation of the model, and the proposed method is verified by simulative results on modified IEEE 33-bus system.