This two-part paper presents a generic methodology for measuring the short-term voltage stability(STVS)of power systems dominated by inverter-based resources(IBRs),which introduces the concept of generalized voltage d...This two-part paper presents a generic methodology for measuring the short-term voltage stability(STVS)of power systems dominated by inverter-based resources(IBRs),which introduces the concept of generalized voltage damping(GVD)for quantifying STVS from both global and local perspectives.It leads to a model-independent approach to assessing the voltage stability,the system strength,and the capability of dynamic devices to support voltage during transient process.Part I of this paper focuses on deriving the system-wise generalized voltage damping(sGVD)index and its applications.The sGVD index is defined as the decay rate of voltage-related transient energy(VTE)dissipated on the(aggregated)buses of the power system,which can be obtained using the maximum Lyapunov exponent(MLE)technique.The proposed sGVD index is theoretically demonstrated to capture the actual voltage damping of devices and to be strongly linked with STVS.These unique properties enable a model-independent approach to measuring STVS and system strength,even in the presence of heterogeneous and strongly nonlinear dynamics of IBRs.We verify the theoretical results by conducting simulations on the modified IEEE 39-bus system and two large-scale practical power systems with integration of massive renewable resources,demonstrating the effectiveness and practicality of the methodology.展开更多
Gully erosion can lead to the destruction of farmland and the reduction in crop yield.Gully mapping from remote sensing images is critical for quickly obtaining the distribution of gullies at regional scales and arran...Gully erosion can lead to the destruction of farmland and the reduction in crop yield.Gully mapping from remote sensing images is critical for quickly obtaining the distribution of gullies at regional scales and arranging corresponding prevention and control measures.The narrow and irregular shapes and similar colors to the surrounding farmland make mapping erosion gullies in sloping farmland from remote sensing images challenging.To implement gully erosion mapping,we developed a small training samples-oriented lightweight deep leaning model,called asymmetric non-local LinkNet(ASNL-LinkNet).The ASNL-LinkNet integrates global context information through an asymmetric non-local operation and conducts multilayer feature fusion to improve the robustness of the extracted features.Experiment results show that the proposed ASNL-LinkNet achieves the best performance when compared with other deep learning methods.The quantitative evaluation results in the three test areas show that the F1-score of erosion gully recognition varies from 0.62 to 0.72.This study provides theoretical reference and practical guidance for monitoring erosion gullies on slope farmland in the black soil region of Northeast China.展开更多
基金supported by the Science and Technology Project of State Grid Corporation of China(No.5100-202355765A-3-5-YS).
文摘This two-part paper presents a generic methodology for measuring the short-term voltage stability(STVS)of power systems dominated by inverter-based resources(IBRs),which introduces the concept of generalized voltage damping(GVD)for quantifying STVS from both global and local perspectives.It leads to a model-independent approach to assessing the voltage stability,the system strength,and the capability of dynamic devices to support voltage during transient process.Part I of this paper focuses on deriving the system-wise generalized voltage damping(sGVD)index and its applications.The sGVD index is defined as the decay rate of voltage-related transient energy(VTE)dissipated on the(aggregated)buses of the power system,which can be obtained using the maximum Lyapunov exponent(MLE)technique.The proposed sGVD index is theoretically demonstrated to capture the actual voltage damping of devices and to be strongly linked with STVS.These unique properties enable a model-independent approach to measuring STVS and system strength,even in the presence of heterogeneous and strongly nonlinear dynamics of IBRs.We verify the theoretical results by conducting simulations on the modified IEEE 39-bus system and two large-scale practical power systems with integration of massive renewable resources,demonstrating the effectiveness and practicality of the methodology.
基金supported by the National Natural Science Foundation of China(42201419).
文摘Gully erosion can lead to the destruction of farmland and the reduction in crop yield.Gully mapping from remote sensing images is critical for quickly obtaining the distribution of gullies at regional scales and arranging corresponding prevention and control measures.The narrow and irregular shapes and similar colors to the surrounding farmland make mapping erosion gullies in sloping farmland from remote sensing images challenging.To implement gully erosion mapping,we developed a small training samples-oriented lightweight deep leaning model,called asymmetric non-local LinkNet(ASNL-LinkNet).The ASNL-LinkNet integrates global context information through an asymmetric non-local operation and conducts multilayer feature fusion to improve the robustness of the extracted features.Experiment results show that the proposed ASNL-LinkNet achieves the best performance when compared with other deep learning methods.The quantitative evaluation results in the three test areas show that the F1-score of erosion gully recognition varies from 0.62 to 0.72.This study provides theoretical reference and practical guidance for monitoring erosion gullies on slope farmland in the black soil region of Northeast China.
