计及VSC运行约束的交直流混合配电网分布式优化调度方法

Distributed Optimal Scheduling of Hybrid AC-DC Distribution Grid Considering VSC Operation Constraints

分布式调度可有效克服由于通信能力限制及子系统分属不同利益主体而引发的生产信息难以集中的问题,更有利于发挥交直流混合配电网在网损降低、新能源消纳方面的优势。然而,VSC运行特性方程及配电网交流潮流约束的高度非凸非线性导致传统方法求解分布式调度问题变得异常困难。提出了一种VSC运行特性方程的线性化方法,并结合配电网潮流线性化方程,将各子系统优化问题转化为混合整数线性规划问题,保证了子问题的收敛性及解的全局最优性,并采用目标分析级联法对各子问题进行分布式优化求解。最后通过构建交直流混合配电网系统仿真算例,验证了所提算法的精确性、收敛性以及在不同规模复杂系统下的通用性,算例同时充分反映出分布式调度可有效保护生产主体隐私、降低配电网通信能力要求,适应未来区域自治配电网系统的发展需要。

Distributed scheduling can effectively overcome the difficulties in concentrating production information due to the communication capacity limitations and the subsystems belonging to different stakeholders.And it is more conductive to take the advantage of hybrid AC-DC distribution grid(HDG)in reducing losses and absorbing renewable energy generation.However,the high nonlinearity and nonconvexity of VSC operation functions and power flow constraints are huge obstacles to solve distributed optimal scheduling problems by the traditional methods.In this paper,a linear approximation method for VSC operation functions is proposed,transforming all the subproblems into mixed-integer linear programming problems,which guarantees the convergence and the global optimality of the subproblems.Then based on analytical target cascading,the distributed scheduling is applied to collaborate all the subproblems.Finally,with the case study of several HDG systems of different sizes,the correctness and versatility of the proposed algorithm are fully verified.The cases also fully reflect that distributed scheduling can effectively protect the privacy of production entities,reduce the requirements for distribution grid communication capabilities,and meet the development needs of future regional autonomous distribution grids.