摘要：Intelligent structures like zero Poisson’s ratio(ZPR)cellular structures have been widely applied to the engineering fields such as morphing wings in recent decades,owing to their outstanding characteristics including light weight and low effective modulus. In-plane and out-of-plane mechanical properties of ZPR cellular structures are investigated in this paper. A theoretical method for calculating in-plane tensile modulus,in-plane shear modulus and out-of-plane bending modulus of ZPR cellular structures is proposed,and the impacts of the unit cell geometrical configurations on in-plane tensile modulus,in-plane shear modulus and out-of-plane bending modulus are studied systematically based on finite element(FE)simulation. Experimental tests validate the feasibility and effectiveness of the theoretical and FE analysis. And the results show that the in-plane and out-of-plane mechanical properties of ZPR cellular structures can be manipulated by designing cell geometrical parameters.

摘要：远距离、大容量、交直流混合运行电网中,交直流系统间的相互影响非常复杂。文中以南方电网交直流混联系统运行实例为基础,讨论了直流系统控制功能在交流系统故障期间的作用,分析了交流系统故障时可能误动的相关直流保护监视功能及换流变和站用变保护等,并给出了相应的改进建议。这不仅有助于提高直流输电系统的运行维护水平,确保交直流系统的安全稳定运行,还为未来直流输电系统的设计、交直流输电系统控制保护功能的合理配合等提供了有益的参考。