基于轨迹灵敏度的紧急切负荷优化算法

超/特高压直流远距离、大容量输电使受端电网发生大功率缺额的概率增加。为防御失去大电源导致的电网安全稳定破坏,提出了一种兼顾暂态安全性和经济性的紧急切负荷优化模型,并设计了高效求解方法。优化模型以总切负荷代价最小为目标,计及暂态电压安全、暂态频率安全和切负荷量约束。暂态安全性均基于时域轨迹严格评估,是带时域参数约束的大规模非线性规划问题。分析了问题最优解的特征,针对带时域参量约束的非线性规划无法直接求解的问题,利用轨迹灵敏度将安全约束线性化,将问题转化为线性规划求解,并通过逐次迭代保证解的一致性。以实际省级电网为例进行仿真分析,验证了算法的有效性。

Emergency Load Shedding Optimization Algorithm Based on Trajectory Sensitivity

Large-scale power exchanges over long distance through high/ultra-high voltage AC/DC transmission systems increase the probability of sudden loss of bulk power in the receiving-end power systems. To prevent such accident from deteriorating the security, an emergency load shedding mathematical model and an efficient trajectory sensitivity based algorithm are proposed, which consider both the transient security of power system and the economics of load shedding. The model, whose objective is to minimize the total load shedding cost, includes constraints on transient voltage security, transient frequency security and the load to be shed. Transient voltage and frequency security is accurately assessed based on the time-domain trajectory. As such a model is a large-scale nonlinear programming problem with time-domain parameter constraints incapable of direct solution, the security constraints are linearized by trajectory sensitivity for solution as a linear programming. The consistency of the solution is guaranteed by iteration, the validity of the algorithm tested and verified through a provincial power system.