具有相同机组水火电调度问题的新算法

A NEW METHOD FOR SCHEDULING HYDRO- THERMAL SYSTEMS WITH IDENTICAL UNITS

对Lagrangian松弛法求解水火电调度问题时由相同机组引起解震荡现象进行了研究。通过一个例子分析了震荡产生的根本原因。对此 ,在松弛函数中引入了惩罚项并采用了伪次梯度法来修正乘子。新算法在求解低层子问题时并不同时求解 ,使震荡现象在很大程度上得以克服 ,同时可大幅度地降低偶解对约束的违反程度。通过简单的例子和对一个包含两组相同机组的短期发电调度问题的计算表明 ,对偶解的约束违反程度明显地降低 ,解震荡明显地减弱且最后可行解的质量有显著的改善。

Solution oscillation caused by identical units when using Lagrangian relaxation based algorithm for hydro thermal scheduling is analyzed in this paper. The homogenous oscillation issue is studied through an example. A penalty term is introduced to the Lagrangian and a surrogate subgradient algorithm is used to update the multipliers.Since the homogeneous subproblems are not solved simultaneously, the oscillation can be avoided or at least alleviated.Numerical testing for the example and a short term generation scheduling problem with two groups of identical units demonstrates that constraint violation of the dual solution and solution oscillation are greatly reduced, and the final feasible schedule is significantly improved.