以统一潮流控制器(unified power flow controller,UPFC)为代表的灵活交流输电技术(flexible AC transmission system,FACTS)可实现传输功率的合理分布、优化系统资源,提高系统的稳定性和可靠性。该文基于内点优化方法,提出计及UPFC的...以统一潮流控制器(unified power flow controller,UPFC)为代表的灵活交流输电技术(flexible AC transmission system,FACTS)可实现传输功率的合理分布、优化系统资源,提高系统的稳定性和可靠性。该文基于内点优化方法,提出计及UPFC的无功优化模型,以系统有功网损最小为目标函数,采用UPFC电压源模型,将其作用等效为一系列电压和功率的约束,直接放到内点法的约束中,在不同的负荷运行方式下进行优化分析。在IEEE-30节点系统测试中发现,引入UPFC后系数矩阵的维数会有所增加,但不会影响其收敛性。算例就系统网损和电压指标对装设UPFC前后进行比较,并给出最优控制方案下UPFC的参数值。结果表明该方法是可行的、有效的,取得很好的效果。展开更多
电力系统大停电后系统的快速恢复是电力系统一直以来要解决的重要问题。通过对现有黑启动模型的分析发现,针对全黑情况下启动全网的所有发电机时,现有的最优目标设置和最优问题描述有可能导致一台发电机爬坡而其他发电机等待的现象。为...电力系统大停电后系统的快速恢复是电力系统一直以来要解决的重要问题。通过对现有黑启动模型的分析发现,针对全黑情况下启动全网的所有发电机时,现有的最优目标设置和最优问题描述有可能导致一台发电机爬坡而其他发电机等待的现象。为解决这一问题,充分考虑发电机的物理调节特性,提出描述实际问题的变约束的最大值最小的优化模型,并通过引入时间变量t,将变约束的最大值最小优化问题等价为内点法可解的定约束最优潮流(optical power flow,OPF)问题,克服了最优潮流中求解变约束最大值最小问题的难点,提出计及发电机出力特性的电力系统黑启动优化计算策略。IEEE 30节点标准系统的仿真结果表明,该方法有效,可明显缩短启动时间。该成果已经成功用于电力系统自愈决策系统软件,在广东电网公司投运。展开更多
为了准确评估风电场接入电网对系统可用输电能力(Available Transfer Capability,ATC)的影响,针对风电并网系统的概率可用输电能力计算展开研究,详细分析不同风电并网情况下ATC的变化规律。首先基于风速Weibull分布,建立了大型风电场输...为了准确评估风电场接入电网对系统可用输电能力(Available Transfer Capability,ATC)的影响,针对风电并网系统的概率可用输电能力计算展开研究,详细分析不同风电并网情况下ATC的变化规律。首先基于风速Weibull分布,建立了大型风电场输出功率数学模型;进而采用原-对偶内点法完成风电并网系统可用输电能力单一样板值的求解。在此基础上,采用蒙特卡罗仿真法从广义角度对风电并网系统的ATC进行概率评估。仿真结果表明,所提算法能够有效评估风电这种波动性电源对ATC的影响。研究成果可为风电并网系统安全经济性能评估提供有效参考信息,对未来电网规划扩建具有指导意义。展开更多
Recent experience has shown that interior-point methods using a log barrierapproach are far superior to classical simplex methods for computing solutions to large parametricquantile regression problems. In many large ...Recent experience has shown that interior-point methods using a log barrierapproach are far superior to classical simplex methods for computing solutions to large parametricquantile regression problems. In many large empirical applications, the design matrix has a verysparse structure. A typical example is the classical fixed-effect model for panel data where theparametric dimension of the model can be quite large, but the number of non-zero elements is quitesmall. Adopting recent developments in sparse linear algebra we introduce a modified version of theFrisch-Newton algorithm for quantile regression described in Portnoy and Koenker[28]. The newalgorithm substantially reduces the storage (memory) requirements and increases computational speed.The modified algorithm also facilitates the development of nonparametric quantile regressionmethods. The pseudo design matrices employed in nonparametric quantile regression smoothing areinherently sparse in both the fidelity and roughness penalty components. Exploiting the sparsestructure of these problems opens up a whole range of new possibilities for multivariate smoothingon large data sets via ANOVA-type decomposition and partial linear models.展开更多
文摘以统一潮流控制器(unified power flow controller,UPFC)为代表的灵活交流输电技术(flexible AC transmission system,FACTS)可实现传输功率的合理分布、优化系统资源,提高系统的稳定性和可靠性。该文基于内点优化方法,提出计及UPFC的无功优化模型,以系统有功网损最小为目标函数,采用UPFC电压源模型,将其作用等效为一系列电压和功率的约束,直接放到内点法的约束中,在不同的负荷运行方式下进行优化分析。在IEEE-30节点系统测试中发现,引入UPFC后系数矩阵的维数会有所增加,但不会影响其收敛性。算例就系统网损和电压指标对装设UPFC前后进行比较,并给出最优控制方案下UPFC的参数值。结果表明该方法是可行的、有效的,取得很好的效果。
文摘电力系统大停电后系统的快速恢复是电力系统一直以来要解决的重要问题。通过对现有黑启动模型的分析发现,针对全黑情况下启动全网的所有发电机时,现有的最优目标设置和最优问题描述有可能导致一台发电机爬坡而其他发电机等待的现象。为解决这一问题,充分考虑发电机的物理调节特性,提出描述实际问题的变约束的最大值最小的优化模型,并通过引入时间变量t,将变约束的最大值最小优化问题等价为内点法可解的定约束最优潮流(optical power flow,OPF)问题,克服了最优潮流中求解变约束最大值最小问题的难点,提出计及发电机出力特性的电力系统黑启动优化计算策略。IEEE 30节点标准系统的仿真结果表明,该方法有效,可明显缩短启动时间。该成果已经成功用于电力系统自愈决策系统软件,在广东电网公司投运。
文摘为了准确评估风电场接入电网对系统可用输电能力(Available Transfer Capability,ATC)的影响,针对风电并网系统的概率可用输电能力计算展开研究,详细分析不同风电并网情况下ATC的变化规律。首先基于风速Weibull分布,建立了大型风电场输出功率数学模型;进而采用原-对偶内点法完成风电并网系统可用输电能力单一样板值的求解。在此基础上,采用蒙特卡罗仿真法从广义角度对风电并网系统的ATC进行概率评估。仿真结果表明,所提算法能够有效评估风电这种波动性电源对ATC的影响。研究成果可为风电并网系统安全经济性能评估提供有效参考信息,对未来电网规划扩建具有指导意义。
基金This research was partially supported by NSF grant SES-02-40781.
文摘Recent experience has shown that interior-point methods using a log barrierapproach are far superior to classical simplex methods for computing solutions to large parametricquantile regression problems. In many large empirical applications, the design matrix has a verysparse structure. A typical example is the classical fixed-effect model for panel data where theparametric dimension of the model can be quite large, but the number of non-zero elements is quitesmall. Adopting recent developments in sparse linear algebra we introduce a modified version of theFrisch-Newton algorithm for quantile regression described in Portnoy and Koenker[28]. The newalgorithm substantially reduces the storage (memory) requirements and increases computational speed.The modified algorithm also facilitates the development of nonparametric quantile regressionmethods. The pseudo design matrices employed in nonparametric quantile regression smoothing areinherently sparse in both the fidelity and roughness penalty components. Exploiting the sparsestructure of these problems opens up a whole range of new possibilities for multivariate smoothingon large data sets via ANOVA-type decomposition and partial linear models.
