基金项目:国家自然科学基金(51667007);中国南方电网有限责任公司重点科技项目(GZKJQQ00000417);贵州省科技创新人才团队项目([2018]5615),Guizhou Province Science and Technology Innovation Talent Team Project([2018]5615)
AC and DC power flow calculation based on alternate iteration is the basis of flexible interconnected power grid research. It can adapt to various control modes of voltage source converter (voltage source converter, VSC), and have good inheritance for the mature AC flow calculation method. However, due to the coupling relationship between AC and DC systems, the algorithm needs to be iterated alternately. This paper first analyzes the steady state model of the converter and its common control mode, the steady state model of the DC power grid, and then derives the reasons that the alternating iterative method and alternate iterative method of the flexible interconnected system need to be iterated many times. A new VSC based power flow decoupling algorithm for the flexible interconnected power grid is proposed. On the basis of not redividing the boundary of the AC and DC system, by the two processing of the active control parameters of the VSC, the advantages of the alternating iterative method are inherited and the alternating iteration can be avoided, which makes the power flow calculation more concise and closer to the actual model, so that the calculation of the power flow of the flexible interconnected power grid is greatly reduced. Finally, the effectiveness and flexibility of the proposed algorithm are verified by two flexible interconnected systems formed by IEEE9 nodes and IEEE30 nodes.