基于Simplex算法的高压直流输电分段变速率VDCOL研究

为了改善高压直流系统的故障后的恢复性能，在研究低压限流单元（Voltage Dependent Current Order Limiter，VDCOL）对直流系统无功功率消耗和电压稳定性影响的基础之上，提出了一种通过将电压下降或恢复过程划分为几个不同的阶段，并在每个阶段根据电压水平的不同而设置不同的功率恢复速率的分段变速率低压限流单元（Piecewise Variable Rate VDCOL，PVR-VDCOL）的控制方法。推导了控制器初值的计算公式，制定了利用Simplex算法优化控制器参数的流程，重点分析了分段数目对控制器性能的影响，在PSCAD/EMTDC中的仿真结果表明所提出的PVR-VDCOL能够有效改善直流系统的恢复性能。

Study of HVDC Piecewise Variable Rate VDCOL Based on Simplex Algorithm

In order to improve the performance of failure recovery characteristic of the HVDC, a novel VDCOL control method called Piecewise Variable Rate VDCOL is proposed that divide the voltage drop or recovery process into several different stages which have different power recovery rate according to the Voltage level. The formula for calculating the initial value of the controller is derived; the strategy using Simplex algorithm to optimize the controller parameters is designed, and the impact of the number of segments on the controller performance is analyzed. The simulation results in PSCAD / EMTDC show that the proposed PVR-VDCOL control method can effectively improve the failure recovery performance of the HVDC system.