基于简化零空间内点法VSC-HVDC离散化最优潮流的研究

Research on the optimal power flow of VSC-HVDC based on the simplified null space interior point method

在求解含电压源换流器的高压直流输电(Voltage Source Converter based High Voltage Direct Current,VSC-HVDC)的交直流系统最优潮流(Optimal Power Flow,OPF)问题时,常使用原对偶内点法或智能算法。但原对偶内点法无法很好地解决含离散变量的OPF(如无功优化),而智能算法在解决此类问题时易陷入局部最优解,同时计算时间过长。因此,提出一种含离散惩罚函数的简化零空间内点算法。算法的主要思想是以简化零空间内点法(下称S-NSIPM)为框架,对连续变量进行优化,当收敛函数小于一定值时,在离散量的计算中引入罚函数,同时随着迭代量差值的变化随时调整罚函数的罚因子的大小。通过算例表明,该算法稳定性高,寻优和适应能力强,能够很好地解决含VSC-HVDC交直流系统的离散变量的优化问题。

To solve the optimal power flow problem of VSC-HVDC system, the primal dual interior point method or intelligent algorithm is often used. However, the primal dual interior point method can not solve the OPF （such as reactive power optimization） with discrete variables. And intelligent algorithm is easy to fall into local optimal solution when solving this kind of problem and the computation time is too long. Therefore, a simplified null space interior point algorithm with discrete penalty function is proposed. The main idea of the algorithm is to optimize continuous variables within the framework of S-NSIPM. When the convergence function is less than a certain value, it adds penalty function into the calculation of discrete quantity, at the same time adjusts the penalty factor as the iteration between the iteration quantity changes. Numerical examples show that the algorithm has high stability, good adaptability and strong adaptability, and can solve the optimization problem of VSC-HVDC system with discrete variables.