中文摘要：

如何精确、快速地处理离散变量是求解大规模电力系统无功优化问题的关键和难点。提出了基于Sigmoid函数连续化的无功优化模型，并应用现代内点法进行求解。所提方法先将离散量当作连续量处理，进行无功优化计算，快速寻求离散变量的激活点；再以所得的结果作为初始解，引入Sigmoid函数对离散变量进行连续化处理，实现精确快速求解含离散变量的电力系统无功优化问题。大量仿真计算结果表明，所提方法具有良好的收敛性和计算效率，对求解大规模系统无功优化问题具有很好的应用前景。

英文摘要：

How to deal with the discrete variables accurately and efficiently is the key issue and difficulty for solving the reactive power optimization of large-scale power systems. This paper presents a continuous model for solving reactive power optimization of power systems with discrete variables. The new model is solved by the modem interior point method. The proposed method includes two steps. Firstly, the reactive power optimization is calculated for obtaining the activation points of the discrete variables, when discrete variables treated as continuous variables. And then, treat the discrete variables continuously by introducing Sigmoid function. Therefore the reactive power optimization with discrete variables can be calculated accurately and efficiently based on the results of the last step. Extensive numerical simulations result show that the proposed algorithm possesses good convergence and high computational efficiency, and is available to solve reactive power optimization of large-scale power systems.