The on-line coordinated control strategy among multi-voltage controls is important to keep voltage security in post-fault systems. Based on the wide area measuring information, the energy function, which can qualify t...The on-line coordinated control strategy among multi-voltage controls is important to keep voltage security in post-fault systems. Based on the wide area measuring information, the energy function, which can qualify the impacts of the different control actions on voltage of different nodes, is proposed. And then, considering the impacts of different control actions on the node voltage being treated as a weight matrix, the energy margin is used as the objective function and the reactive power margin is innovatively used as the constraint to regulate the control actions globally according to the weight values. At last, the objective functions are solved to get the optimal global coordinated control strategies. The proposed method is identified in an IEEE-30 Bus system and the simulation results show that it effectively improves the voltage stability.展开更多
This paper investigates the flux-pinning-induced stress behaviors in a long superconducting slab with a central cuboid hole.The distribution of flux density is analytically derived for the critical current density of ...This paper investigates the flux-pinning-induced stress behaviors in a long superconducting slab with a central cuboid hole.The distribution of flux density is analytically derived for the critical current density of Kim model by considering the effects of the hole.The concentration of stress for both of the zero-field cooling(ZFC)and the field cooling(FC)magnetization processes are investigated through numerical simulation by using finite element method.The results indicate the potential failure mode varies with the height-width ratio and the dimensions of the hole.Different to the case of infinite hole height,the stress concentration behavior for the FC process is more critical when the dimensions of the hole are similar.The findings in this paper are useful for understanding of the degrade mechanism of superconductor in service and the design of new system.展开更多
基金supported by the National Natural Science Foundation of China under Grant No.51007006the Fundamental Research Funds for the Central Universities under Grant No.ZYGX2012J159
文摘The on-line coordinated control strategy among multi-voltage controls is important to keep voltage security in post-fault systems. Based on the wide area measuring information, the energy function, which can qualify the impacts of the different control actions on voltage of different nodes, is proposed. And then, considering the impacts of different control actions on the node voltage being treated as a weight matrix, the energy margin is used as the objective function and the reactive power margin is innovatively used as the constraint to regulate the control actions globally according to the weight values. At last, the objective functions are solved to get the optimal global coordinated control strategies. The proposed method is identified in an IEEE-30 Bus system and the simulation results show that it effectively improves the voltage stability.
基金supported by the National Natural Science Foundation of China(Grants 11872257,11572358).
文摘This paper investigates the flux-pinning-induced stress behaviors in a long superconducting slab with a central cuboid hole.The distribution of flux density is analytically derived for the critical current density of Kim model by considering the effects of the hole.The concentration of stress for both of the zero-field cooling(ZFC)and the field cooling(FC)magnetization processes are investigated through numerical simulation by using finite element method.The results indicate the potential failure mode varies with the height-width ratio and the dimensions of the hole.Different to the case of infinite hole height,the stress concentration behavior for the FC process is more critical when the dimensions of the hole are similar.The findings in this paper are useful for understanding of the degrade mechanism of superconductor in service and the design of new system.
