基于内点法的交直流系统电压稳定性评估

Voltage Stability Assessment for AC/DC Power Systems Based on Interior Point Method

针对交直流系统稳定分析时直流变量约束、运行方式调整以及计算收敛性问题,基于原始-对偶内点法提出分段求解交直流系统负荷裕度的新算法。由交直流网络间的耦合关系和换流器转换方程,推导出直角坐标系交直流系统的Jacobi、Hessian矩阵,进而用原始-对偶内点法求解直流控制方式不变的交直流系统的负荷裕度。交直流系统直流控制方式会发生调整,提出分段求解负荷裕度的方法,即分别用内点法求解系统不同直流控制方式的最大负荷增量再求和,该方法能方便考虑直流变量约束及运行方式的调整。经算例验证该算法在交直流系统稳定计算中对初始值选择要求不高,收敛迭代次数少。

Considering the variable constraints of DC system, the adjustment of operation mode and convergence during assessing the voltage stability of AC/DC power systems, this paper proposes a new segment method for solving load margin of AC/DC power system based on the primal-dual interior point algorithm. The Jalobian and Hessian matrix of AC/DC system in the rectangular coordinates is extrapolated with the coupled relationship of AC/DC network and the conversion function of converters. Then the load margin of AC/DC system with a sigle DC control mode, can be calculated by interior point method. Considering the switch of the DC control mode, a new load margin solution is presental that is to solve the maximum load incremental under each DC control mode separately and add them together. The method is characterized by its convenience of considering varialle constraints of DC system and adjustment of DC operation mode. Simulation results show that the method is not sense to the initial value and convergent swiftly.