电力现货市场优化出清模型的难点是考虑安全约束的机组组合(security constrained unit commitment,SCUC)模型。构建一个好的SCUC模型以提升求解速度是长期以来的研究热点。随着省电力系统规模的不断发展,以及国内省间电力现货市场的运...电力现货市场优化出清模型的难点是考虑安全约束的机组组合(security constrained unit commitment,SCUC)模型。构建一个好的SCUC模型以提升求解速度是长期以来的研究热点。随着省电力系统规模的不断发展,以及国内省间电力现货市场的运行,现货市场对于出清模型的求解效率需求更为突出。该文对机组组合模型的研究历程进行详细综述,总结提出机组运行出力约束、出力上限约束、爬坡约束强化建模的机组运行模型;基于图论在线性最优潮流计算中的应用,构建输电网的环流潮流计算模型并引入SCUC模型,最终构建了一套可进一步提升求解效率的电力现货市场出清模型。最后通过多个大规模算例的计算分析表明,所提模型在保证不损失求解精度的同时,可有效提升求解效率,且对于阻塞频发的电力系统,优越性更为明显。展开更多
Currently, the flow field of annular seals disturbed by the circular whirl motion of rotors is usually solved using computational fluid dynamics(CFD) to evaluate the five rotordynamic coefficients. The simulations are...Currently, the flow field of annular seals disturbed by the circular whirl motion of rotors is usually solved using computational fluid dynamics(CFD) to evaluate the five rotordynamic coefficients. The simulations are based on the traditional quasi-steady method. In this work, an improved quasi-steady method along with the transient method was presented to compute the rotordynamic coefficients of a long seal. By comparisons with experimental data, the shortcomings of quasi-steady methods have been identified. Then, the effects of non-uniform incoming flow on seal dynamic coefficients were studied by transient simulations. Results indicate that the long seal has large cross stiffness k and direct mass M which are not good for rotor stability, while the transient method is more suitable for the long seal for its excellent performance in predicting M. When the incoming flow is non-uniform, the stiffness coefficients vary with the eccentric directions. Based on the rotordynamic coefficients under uniform incoming flow, the linearized fluid force formulas, which can consider the effects of non-uniform incoming flow, have been presented and can well explain the varying-stiffness phenomenon.展开更多
文摘电力现货市场优化出清模型的难点是考虑安全约束的机组组合(security constrained unit commitment,SCUC)模型。构建一个好的SCUC模型以提升求解速度是长期以来的研究热点。随着省电力系统规模的不断发展,以及国内省间电力现货市场的运行,现货市场对于出清模型的求解效率需求更为突出。该文对机组组合模型的研究历程进行详细综述,总结提出机组运行出力约束、出力上限约束、爬坡约束强化建模的机组运行模型;基于图论在线性最优潮流计算中的应用,构建输电网的环流潮流计算模型并引入SCUC模型,最终构建了一套可进一步提升求解效率的电力现货市场出清模型。最后通过多个大规模算例的计算分析表明,所提模型在保证不损失求解精度的同时,可有效提升求解效率,且对于阻塞频发的电力系统,优越性更为明显。
基金Project(51276213)supported by the National Natural Science Foundation of ChinaProject(2013BAF01B00)supported by the National Science and Technology Support Program of China
文摘Currently, the flow field of annular seals disturbed by the circular whirl motion of rotors is usually solved using computational fluid dynamics(CFD) to evaluate the five rotordynamic coefficients. The simulations are based on the traditional quasi-steady method. In this work, an improved quasi-steady method along with the transient method was presented to compute the rotordynamic coefficients of a long seal. By comparisons with experimental data, the shortcomings of quasi-steady methods have been identified. Then, the effects of non-uniform incoming flow on seal dynamic coefficients were studied by transient simulations. Results indicate that the long seal has large cross stiffness k and direct mass M which are not good for rotor stability, while the transient method is more suitable for the long seal for its excellent performance in predicting M. When the incoming flow is non-uniform, the stiffness coefficients vary with the eccentric directions. Based on the rotordynamic coefficients under uniform incoming flow, the linearized fluid force formulas, which can consider the effects of non-uniform incoming flow, have been presented and can well explain the varying-stiffness phenomenon.
