Due to increased penetration of renewable energies,DC links and other emerging technologies,power system operation and planning have to cope with various uncertainties and risks.In order to solve the problems of excee...Due to increased penetration of renewable energies,DC links and other emerging technologies,power system operation and planning have to cope with various uncertainties and risks.In order to solve the problems of exceeding short circuit current and multi-infeed DC interaction,a coordinated optimization method is presented in this paper.Firstly,a branch selection strategy is proposed by analyzing the sensitivity relationship between current limiting measures and the impedance matrix.Secondly,the impact of network structure changes on the multi-infeed DC system is derived.Then the coordinated optimization model is established,which considers the cost and effect of current limiting measures,the tightness of network structure and the voltage support capability of AC system to multiple DCs.Finally,the non-dominated sorting genetic algorithm II combining with the branch selection strategy,is used to find the Pareto optimal schemes.Case studies on a planning power system demonstrated the feasibility and speediness of this method.展开更多
HVDC auxiliary power control can significantly improve the transient stability of AC/DC power grid.An HVDC adaptive emergency power support method based on unbalanced power on line estimation is proposed in this paper...HVDC auxiliary power control can significantly improve the transient stability of AC/DC power grid.An HVDC adaptive emergency power support method based on unbalanced power on line estimation is proposed in this paper.By establishing the extended state equation of the system,the on line dynamic estimation of unbalanced power of the system was realized.On this basis,power support was realized based on the principle of the ladder increment.The optimal DC was selected by the power support factor,and the emergency power support controller was installed on the DC.This emergency power support method can realize dynamic optimal power support with minimized control cost.The three infeed HVDC system was built on PSCAD.The simulation results show the effectiveness of the proposed method.展开更多
Adenomyosis (AD) refers to the endometrium (including glands and stroma) into myometrium gr owth of pathological changes, with the delay of women's childbea ring age, the pa ti ents with AD-associated infertility ...Adenomyosis (AD) refers to the endometrium (including glands and stroma) into myometrium gr owth of pathological changes, with the delay of women's childbea ring age, the pa ti ents with AD-associated infertility increased significantly. Although scholars disagreed about the effect of AD on infertility, more and more evidence showed that AD was closely related to the str uct ural and func ti onal defects of the eutopic endomet rium and myomet rial junc tional zone (MJZ), which may lead to embryo implantation failure and infertility. With the rapid development of imaging technology, the accuracy of diagnose AD has been enhanced, more and more infertility patients were diagnosed with AD. At the same time, a series of pathogenic hypothesis have been proposed to explain the relationship between AD. In addition, AD may influence the patient's reproductive function by affecting sperm transport, embryo implantation, altering uterine peristalsis, influencing the structure and function of endometrium, and changing the intrauterine environment. At present, the treatment of AD-associated infertility is similar to the treatment of AD. The commonly used treatment methods include drug therapy, conservative operative treatment, drug combination surgery, and Chinese medicine treatment and so on. The clinical and experimental studies of AD complicated with infertility and its possible pathogenesis and treatment in recent years are reviewed in this article.展开更多
基金This work was supported by State Grid Corporation of China,Major Projects on Planning and Operation Control of Large Scale Grid under Grant SGCC-MPLG020-2012.
文摘Due to increased penetration of renewable energies,DC links and other emerging technologies,power system operation and planning have to cope with various uncertainties and risks.In order to solve the problems of exceeding short circuit current and multi-infeed DC interaction,a coordinated optimization method is presented in this paper.Firstly,a branch selection strategy is proposed by analyzing the sensitivity relationship between current limiting measures and the impedance matrix.Secondly,the impact of network structure changes on the multi-infeed DC system is derived.Then the coordinated optimization model is established,which considers the cost and effect of current limiting measures,the tightness of network structure and the voltage support capability of AC system to multiple DCs.Finally,the non-dominated sorting genetic algorithm II combining with the branch selection strategy,is used to find the Pareto optimal schemes.Case studies on a planning power system demonstrated the feasibility and speediness of this method.
基金the National Natural Science Foundation of China(Grant No.51607158)the Key Scientific Technological Project in Henan Province(Grant No.192102210075)。
文摘HVDC auxiliary power control can significantly improve the transient stability of AC/DC power grid.An HVDC adaptive emergency power support method based on unbalanced power on line estimation is proposed in this paper.By establishing the extended state equation of the system,the on line dynamic estimation of unbalanced power of the system was realized.On this basis,power support was realized based on the principle of the ladder increment.The optimal DC was selected by the power support factor,and the emergency power support controller was installed on the DC.This emergency power support method can realize dynamic optimal power support with minimized control cost.The three infeed HVDC system was built on PSCAD.The simulation results show the effectiveness of the proposed method.
文摘Adenomyosis (AD) refers to the endometrium (including glands and stroma) into myometrium gr owth of pathological changes, with the delay of women's childbea ring age, the pa ti ents with AD-associated infertility increased significantly. Although scholars disagreed about the effect of AD on infertility, more and more evidence showed that AD was closely related to the str uct ural and func ti onal defects of the eutopic endomet rium and myomet rial junc tional zone (MJZ), which may lead to embryo implantation failure and infertility. With the rapid development of imaging technology, the accuracy of diagnose AD has been enhanced, more and more infertility patients were diagnosed with AD. At the same time, a series of pathogenic hypothesis have been proposed to explain the relationship between AD. In addition, AD may influence the patient's reproductive function by affecting sperm transport, embryo implantation, altering uterine peristalsis, influencing the structure and function of endometrium, and changing the intrauterine environment. At present, the treatment of AD-associated infertility is similar to the treatment of AD. The commonly used treatment methods include drug therapy, conservative operative treatment, drug combination surgery, and Chinese medicine treatment and so on. The clinical and experimental studies of AD complicated with infertility and its possible pathogenesis and treatment in recent years are reviewed in this article.
