A Robust Reserve Scheduling Method Considering Asymmetrical Wind Power Distribution

Nowadays, limited predictability and controllability of wind power are regarded as some bottlenecks to wind generation integration with the power system. This paper introduces a robust reserve scheduling method, where the spinning reserve allocation among conventional units is considered as well.The method applies to asymmetrical wind power distribution,and offers control on the degree of solution's conservatism by changing the robustness budget. Meanwhile, distributional information of wind power is represented by mean value and asymmetrical bounds. Furthermore, the model is converted into a deterministic programming problem with dual theory. Case studies for asymmetrically distributed wind power illustrate its effectiveness.

Grid Strength Assessment for Inhomogeneous Multi-infeed HVDC Systems via Generalized Short Circuit Ratio

Generalized short circuit ratio(g SCR)for grid strength assessment of multi-infeed high-voltage direct current(MIDC)systems is a rigorous theoretical extension of the traditional SCR,which enables SCR to be extended to MIDC systems.However,g SCR is originally based on the assumption of homogeneous MIDC systems,in which all high-voltage direct current(HVDC)converters have an identical control configuration,thus presenting challenges to applications of g SCR to inhomogeneous MIDC systems.To weaken this assumption,this paper applies matrix perturbation theory to explore the possibility of utilization of g SCR into inhomogeneous MIDC systems.Results of numerical experiments show that in inhomogeneous MIDC systems,the previously proposed g SCR can still be used without modification.However,critical g SCR(Cg SCR)must be redefined by considering the characteristics of control configurations of HVDC converter.Accordingly,the difference between g SCR and redefined Cg SCR can effectively quantify the pertinent AC grid strength in terms of the static-voltage stability margin.The performance of the proposed method is demonstrated in a triple-infeed inhomogeneous line commutated converter based high-voltage direct current(LCC-HVDC)system.

Anisotropic Cu@Cu-BTC core-shell nanostructure for memory device

The activity and stability of Cu nanostructures strongly depend on their sizes,morphology and structures.Here we report the preparation of two-dimensional(2 D)Cu@Cu-BTC core-shell nanosheets(NSs).The thickness of the Cu NSs could be tuned to sub-10 nm through a mild etching process,in which the Cu-BTC in situ grow along with the oxidation on the surface of the Cu NSs.This unique strategy can also be extended to synthesize one-dimensional(1 D)Cu@Cu-BTC nanowires(NWs).Furthermore,the obtained Cu@Cu-BTC NSs could be applied as an effective material to the memory device with the write-onceread-many times(WORM)behavior and the high ION/I(OFF)ratio(>2.7×103).

Data-driven Probabilistic Static Security Assessment for Power System Operation Using High-order Moments

In this letter,a new formulation of Lebesgue integration is used to evaluate the probabilistic static security of power system operation with uncertain renewable energy generation.The risk of power flow solutions violating any pre-defined operation security limits is obtained by integrating a semialgebraic set composed of polynomials.With the high-order moments of historical data of renewable energy generation,the integration is reformulated as a generalized moment problem which is then relaxed to a semi-definite program(SDP).Finally,the effectiveness of the proposed method is verified by numerical examples.