基于实时生成定值的高比例新能源电网自适应电流保护

新型电力系统电源侧含有高比例新能源电源,受其状态多样性、布置分散性、输出非线性等影响,电网故障期间短路电流水平下降且不确定性增强,给传统电流保护的整定配合造成困难。为此,结合传统三段式电流保护,提出了一种基于实时生成定值的自适应电流保护方法。该方法计及新能源实际故障输出而生成定值,包括:首先,建立能区分新能源和发电机不同输出特性的等效电源模型,故障前对短路前后不变的模型参数持续辨识;故障发生后,结合就地测量信息获取等效电源模型的变化参数;然后,基于实际故障场景和故障期间新能源实际输出,对分段式电流保护进行实时整定;最后,结合测量值与整定值进行动作判断。故障前的持续辨识,保证了发电机与新能源的有效分离;基于实际故障场景生成定值可计及新能源的整体输出作用,有效应对其分散性、多样性与非线性问题。通过算例对比与分析,验证了所提自适应电流保护方法的可行性与正确性。

Numerical Tools for the Control of the Unsteady Heating of an Airfoil

This paper concerns the real time control of the boundary layer on an aircraft wing. This new approach consists in heating the surface in an unsteady regime using electrically resistant strips embedded in the wing skin. The control of the boundary layer＇s separation and transition point will provide a reduction in friction drag, and hence a reduction in fuel consumption. This new method consists in applying the required thermal power in the different strips in order to ensure the desired temperatures on the aircraft wing. We also have to determine the optimum size of these strips （length, width and distance between two strips）. This implies finding the best mathematical model corresponding to the physics enabling us to facilitate the calculation for any type of material used for the wings. Secondly, the heating being unsteady, and, as during a flight the flow conditions or the ambient temperatures vary, the thermal power needed changes and must be chosen as fast as possible in order to ensure optimal operating conditions.

Interpolation of Lorentz martingale spaces

In this paper,we apply function parameters,introduced by Persson,to real interpolation of Lorentz martingale spaces.Some new interpolation theorems concerning Lorentz martingale spaces are formulated.The results that we obtain generalize some fundamental interpolation theorems in classical martingale Hp theory.