含电压源型换流器直流电网的交直流网络潮流交替迭代方法

摘要

随着电压源型换流器(VSC)及基于VSC的并联型直流电网的不断发展，未来电网会形成含VSC的多直流母线、多直流联络线和多直流负荷的交直流网络。文中分析了 VSC 的稳态模型及其控制方式，详细推导了含VSC直流电网的交直流网络稳态潮流模型，研究了不同控制方式直流电网的潮流求解方法。在此基础上提出了一种通用交直流网络潮流交替迭代方法，该算法根据VSC换流站的不同控制方式在交流侧和直流侧解耦等效，先进行直流电网潮流迭代，后进行交流电网潮流迭代，二者交替计算直至直流电网、换流站和交流电网全部收敛。算法适用于不同的直流电网控制方式且考虑了直流变量约束条件和运行方式的合理调整。最后在改进的 IEEE 57节点交直流电网上，验证了所提出的交替迭代方法的有效性和准确性。%With the steady development of voltage source converter(VSC)and parallel DC grid based on VSC,the future power grid may become hybrid AC/DC networks containing multi-DC buses,multi-DC lines and multi-DC loads.The steady-state model and control mode of VSC are analyzed,and the power flow model of AC/DC networks containing DC grid based on VSC is derived.Then the power flow solution for DC grid with different control modes is studied prior to proposing a generalized alternating iterative power flow algorithm.This algorithm decouples the AC grid and the DC grid according to different control modes of the VSC station.In each iteration of the algorithm,AC grid iteration follows the DC grid iteration.The algorithm will not stop calculating AC and DC alternatively until the DC grid,VSC station and AC grid are all convergent.Diverse control modes of DC grid,the constraint of variables and the change of VSC control mode are taken into consideration.Finally,with the modified IEEE 5 7-bus AC/DC networks,several simulation results clearly verified the feasibility and effectiveness of the proposed algorithm.