潮流计算是电网规划与运行分析的基础,目前一些系统分析工作需要收敛的潮流工况。针对电力系统研究所潮流及暂态稳定程序(power system department,Bonneville Power Administration,PSD-BPA)中运行方式安排时出现的无功潮流无解问题,...潮流计算是电网规划与运行分析的基础,目前一些系统分析工作需要收敛的潮流工况。针对电力系统研究所潮流及暂态稳定程序(power system department,Bonneville Power Administration,PSD-BPA)中运行方式安排时出现的无功潮流无解问题,提出一种无功潮流收敛性的二阶段自动调整方法。对于不收敛的潮流,首先通过节点类型转换将500 kV输电网上含无功补偿的节点转为PV节点,获取量化无功不收敛的指标。其次,按电网分区将转换类型的节点逐步还原,以还原节点的电压幅值及各分区的电压水平为参考制定第一阶段调整策略;通过Floyd算法确定输电网无功调整路径且由节点补偿量进行修正,获得第二阶段调整策略并使潮流恢复收敛。最后,以某省实际电网验证算法在无功潮流收敛性调整方面的有效性。展开更多
A "reaction-extrusion process" has been developed to prepare Zn4Sb3 bulk materials with high thermoelectric performance.The synthesis,densification,and shape-forming of Zn4Sb3 bulk materials were realized si...A "reaction-extrusion process" has been developed to prepare Zn4Sb3 bulk materials with high thermoelectric performance.The synthesis,densification,and shape-forming of Zn4Sb3 bulk materials were realized simultaneously in one hot-extrusion process,and the resulting extrudates had high density with single β-Zn4Sb3 phase.A large extrusion ratio and a small punch speed are advantageous to enhance thermoelectric performance.The extruded Zn4Sb3 materials exhibited excellent thermoelectric performance,for example,the dimensionless thermoelectric figure of merit is 1.77 at 623 K,which is 36% higher compared to conventional hot-pressed materials.On the other hand,the incorporation of 1% SiC nanosized particles into Zn4Sb3 matrix leads to improvements in both thermoelectric and mechanical properties.展开更多
文摘潮流计算是电网规划与运行分析的基础,目前一些系统分析工作需要收敛的潮流工况。针对电力系统研究所潮流及暂态稳定程序(power system department,Bonneville Power Administration,PSD-BPA)中运行方式安排时出现的无功潮流无解问题,提出一种无功潮流收敛性的二阶段自动调整方法。对于不收敛的潮流,首先通过节点类型转换将500 kV输电网上含无功补偿的节点转为PV节点,获取量化无功不收敛的指标。其次,按电网分区将转换类型的节点逐步还原,以还原节点的电压幅值及各分区的电压水平为参考制定第一阶段调整策略;通过Floyd算法确定输电网无功调整路径且由节点补偿量进行修正,获得第二阶段调整策略并使潮流恢复收敛。最后,以某省实际电网验证算法在无功潮流收敛性调整方面的有效性。
文摘A "reaction-extrusion process" has been developed to prepare Zn4Sb3 bulk materials with high thermoelectric performance.The synthesis,densification,and shape-forming of Zn4Sb3 bulk materials were realized simultaneously in one hot-extrusion process,and the resulting extrudates had high density with single β-Zn4Sb3 phase.A large extrusion ratio and a small punch speed are advantageous to enhance thermoelectric performance.The extruded Zn4Sb3 materials exhibited excellent thermoelectric performance,for example,the dimensionless thermoelectric figure of merit is 1.77 at 623 K,which is 36% higher compared to conventional hot-pressed materials.On the other hand,the incorporation of 1% SiC nanosized particles into Zn4Sb3 matrix leads to improvements in both thermoelectric and mechanical properties.
