计及换流器损耗与电压下垂控制的交直流系统最优潮流算法

摘要

An optimal power flow algorithm of AC/DC hybrid power system considering precise converter power losses and voltage-droop control is proposed.Based on the generalized model of voltage source converter (VSC) stations that take into account the converter power losses,an optimal power flow mathematical model of AC/DC power system with VSC based multi-terminal DC (VSC-MTDC) networks is developed.The effects of different control strategies of VSC stations on the setting of optimal variables and equality constraints are deduced in detail.Aiming at the "coupling relationship" problem between the AC side power injection and the converter power loss of droop-control converters,an iterative calculating method for the AC side active power of voltage-droop converters is proposed.Moreover,on the basis of analyzing the construction of Jacobian matrix considering various control strategies,the primal-dual interior point method is used to solve the optimal power flow model.Finally,the modified IEEE 30-bus test system is made use of for case studies of the optimal power flow algorithm's validity,accuracy and versatility.%提出一种考虑换流器精确损耗与电压下垂控制的交直流系统最优潮流计算方法.基于计及换流器精确有功损耗的电压源换流器(VSC)换流站一般模型,建立了多端柔性直流互联交直流系统的最优潮流数学模型,推导了不同控制方式对寻优变量设定和等式约束构建的影响.针对电压下垂控制换流器交流侧有功功率与换流器损耗之间的“耦合”问题,提出了一种下垂控制VSC交流侧有功功率的计算方法.进而,在分析雅可比矩阵构成的基础上,采用步长控制原对偶内点法实现了模型求解.最后通过改进的IEEE 30节点算例仿真,分析了换流器损耗、电压下垂控制方式对最优潮流计算的影响,验证了所提方法的有效性、准确性和适用性.