考虑主导不稳定平衡点变化的电力系统暂态稳定切机控制策略

在考虑不同切机措施导致的主导不稳定平衡点变化的前提下,提出了一种基于切机灵敏度的电力系统暂态稳定切机控制策略。首先将切机后系统暂态稳定裕度表达式中与主导不稳定平衡点相关的部分提取出来,通过建立切机量与主导不稳定平衡点的修正方程,利用牛拉法确定主导不稳定平衡点的变化情况。在此基础上求取系统暂态稳定裕度对不同发电机组的切机灵敏度,最终按照所求切机灵敏度大小制定切机策略。新英格兰10机39节点系统的仿真结果表明,相比于不考虑主导不稳定平衡点变化的切机策略,该策略所求灵敏度及切机量更加准确。同时,该策略求解步骤直接、明确,既考虑了切机控制导致的主导不稳定平衡点的变化情况,又避免了反复求取主导不稳定平衡点时繁琐的计算过程,节省了计算时间。

Generator tripping strategy in transient stability control of a power system considering the change of the controlling unstable equilibrium point

Considering the change of the main unstable equilibrium point caused by different generator tripping measures,a generator tripping strategy based on sensitivity is proposed.First,the part of the transient stability margin related to the controlling unstable equilibrium point is extracted,and then the modified equation of the generator tripping amount and the controlling unstable equilibrium point is established,and the change of the controlling unstable equilibrium point is determined by the Newton-Raphson method.The sensitivity of the transient stability margin of the system to different generators is calculated,and finally the generator tripping strategy is formulated according to the sensitivity.The simulation results on the New England 10 machine 39 node system show that the sensitivity of this strategy is more accurate than that of the cutting strategy without considering the change of the controlling unstable equilibrium point.It can effectively reduce the total generator cutting amount.At the same time,the solution steps of the strategy are direct and clear,which avoids the tedious calculation process and saves calculation time.