基于可再生能源汇集母线电压角速度轨迹的级联断面解列策略

文章研究了两端电势幅值不等时可再生能源汇集母线电压角速度的变化规律,提出了利用可再生能源汇集母线电压角速度来定位振荡中心及失步中心的大规模可再生能源电网级联断面解列策略。首先分析了级联断面的耦合关系及异步振荡过程电压角速度特性,通过可再生能源输送线路两侧电压角速度变化速率相反来确定失步中心位置;然后采用短路阻抗法绘制振荡中心角速度轨迹,以此计算振荡中心分布;最后综合失步中心、振荡中心、孤岛不平衡度及潮流冲击,应用主成分分析法决策解列方案。文章所提出的方法综合考虑解列有效性及解列后系统稳定性指标,提高了解列策略的合理性,使解列过程更加快速、有效。基于西北实际电网的仿真算例,验证了本策略的有效性,显示了该策略判据简单,决策方法合理。

Cascade cross-section decommissioning strategy based on voltage angular velocity trajectory of renewable energy pooling bus

The variation law of the voltage angular velocity of the renewable energy bus is studied when the amplitude of potential at both ends is not equal. A cascade section splitting strategy for large-scale renewable energy grid is also proposed by using the voltage angular velocity of renewable energy bus to locate the oscillation center and the out-of-step center in this paper.Firstly, the coupling relationship of cascade section and the characteristics of voltage angular velocity during asynchronous oscillation are analyzed. The position of out-of-step center is determined by the opposite change rate of voltage angular velocity on both sides of renewable energy transmission line. Then, the angular velocity trajectory of the oscillation center is drawn by the short-circuit impedance method to calculate the oscillation center distribution. Finally,combined with out-of-step center, oscillation center, island imbalance and tidal current impact,the principal component analysis method is used to determine the solution scheme. The proposed method comprehensively considers the splitting effectiveness and the system stability index after splitting, which improves the rationality of the splitting strategy and makes the solution process more rapid and effective. The effectiveness of the strategy is verified by a simulation example based on the actual northwest power grid, which shows that the strategy criterion is simple and the decision method is reasonable.