考虑电压稳定约束的无功优化新模型

A New Model of Optimal Reactive Power Flow Incorporating Voltage Stability Constraints

为了提高电力系统的安全水平,有必要在无功优化中考虑静态电压稳定约束。现有模型以发电机组恒定不变的无功上下限值来确定电压稳定极限,由此可能导致无功的优化运行不满足实际发电机组的运行极限约束。建立了一种含静态电压稳定约束的无功优化新模型。其中,目标函数为正常状态的有功网损最小,约束方程包括正常状态和临界状态的潮流及其他安全约束和电压稳定裕度约束。由于采用一组基于发电机运行极限图的分段函数来准确反映发电机组的无功限制,从而克服了现有模型可能违反发电机组运行极限约束的问题。采用预测-校正原对偶内点法来求解无功优化新模型,通过IEEE30节点系统的仿真计算,验证了本文所建模型的可行性。

For operation security of power systems, voltage stability constraints must be considered in optimal reactive power flow .In the conventional models, voltage stability limits is set up based on a fixed maximum and minimum values of generator reactive power, which may lead to the infeasible result by which the factual capability limits of generators are not satisfied. A new model of optimal reactive power flow incorporating static voltage stability constraints is proposed in this paper. In which, the objective function is the active power losses, and the constraints include two groups of power flow equations respectively for the normal state and the critical state, and those for secure and voltage stability margin. A set of piecewise functions based on generator capability limits is given to depict the actual reactive power constraints of generators, which can overcome the shortage of the conventional model with infeasible result. Predietor-corrector primal-dual interior point method is used for solving the proposed problem in this paper. The numerical results of IEEE30 bus system indicate the feasibility of the proposed model.