The cloaking methods of infinite length coaxial cylindrical and concentric spherical invisibility cloaks in the non-uniform static field are investigated. First, the arbitrary potential function at the infinite boundary is expanded into a series of orthogonal potential functions. When there is only the nth order orthogonal potential function distribution at the infinite boundary, the analytical cloaking conditions of both the infinite length coaxial cylindrical and concentric spherical cloaks are derived. Furthermore, based on the analytical cloaking conditions, the approaching cloaking method is proposed in a complex non-uniform static field which composed of multiple orders potential functions. This method can acquire the optimal cloaking condition and avoid the iteration process by using numerical methods such as the finite element method etc. Finally, three examples are given to verify the correctness of the analytical cloaking conditions and the effectiveness of the approaching cloaking method proposed in this paper.

The invisibility condition of cloak in the Electro-Quasi-Static (EQS) field under the arbitrary transient excitation is given in this paper. Firstly, because electric field with magnetoelectric effect ignored can be attributed to the EQS field which is the transient electric field. In this case, the analytical invisibility conditions of infinite length coaxial cylinders cloaks under arbitrary transient excitation are derived in the EQS field. Then, by the finite element method(FEM) simulation, the correctness of the analytical invisibility condition is verified. Besides, this paper also established the equivalent circuit model for the cloak in the EQS field by the resistance and capacitance network. At last, analytical invisibility conditions of the concentric spheres cloak are also given. By the invisibility conditions proposed in this paper, the cloak could achieve stealth under the transient electric field which will greatly enhance the performance of the cloak.

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-The Online Dynamic Security Assessment& Early Warning System of Power System (PDSA) integrate grid data and model, adopt pre-allocation mechanism, make static stability analysis, transient stability analysis, dynamic stability analysis and advanced assessment of total transfer capacity(TTC). Real-time alarm information of power grid is shown which reflect weak points of the grid. However, with the development of grid structure and data model, only displaying current alarm results that is unable to meet dispatchers' demands through pre-allocation fixed parameters mechanism adopted. This paper introduced combination of dynamic warning online systems and offline systems, which achieve online calculation parameters dynamically adjustment, transient stability curve viewing, analysis and comparison of historical alarm results, report generation. The solution has been successfully applied to state grid, regional grids and provincial grids of china, such as state grid, central china power grid, Hubei grid, which ensure the system's flexibility and stability, improve work efficiency, and provide convenient means for operator.