以直流潮流模型为基础,将计及电网静态安全约束的机组组合问题分解为无安全约束的机组组合问题和计及电网静态安全约束的优化潮流问题2个子优化问题。通过在后者中引入虚拟变量来反映机组组合对输电元件传输限制的牵制及影响,并借用虚拟变量和发电转移因子,构建前者与后者间关联的补充约束条件,从而形成前者随后者变化的影响机制及优化方向的修正手段,由此提出了2个子优化问题间交替求解的算法。该算法充分兼容现有成型方法,符合电力系统实际,对解决电网静态安全对机组组合制约现象,以及对机组组合方案评价,有良好的适应性。
On the basis of direct current (DC) power flow model, the static security-constrained unit commitment problem is decomposed into two sub-problems, (1) the unit commitment problem without security constraints, and (2) the optimal power flow problem with static security constraints. Virtual variables are introduced into sub-problem (2) to reflect the restriction and influence of the unit commitment to transmission elements. The complementary constraints correlating the two sub-problems can be set up by the virtual variables and generation shift factors. This approach models the influence mechanism of sub- problem (1) varies with sub-problem (2). It also provides an effective means to modify the optimization direction. Therefore, an algorithm for solving the two sub-problems alternatively is proposed. The proposed algorithm is sufficiently compatible with the present methods and conforms to the reality of the power systems, as well as has good flexibility to deal with the security restraint phenomenon of the unit commitment and evaluate the results of unit commitment problems.