Simulation Research of Transient Over-voltage on High-voltage Shunt Capacitor Banks

With the development of power systems,a large number of shunt capacitors are used to improve power quality in the distribution network.The shunt capacitor banks are operated much frequently,as a result,the capacitor banks will bear large numbers of over-voltage inevitably.If the over-voltage exceeds certain amplitude,the capacitor will be damaged.This paper aims at the capacitor banks in the 35 kV side of Shanghai Xu-xing 500 kV substation,and applies ATP-EMTP to simulate the over-voltages generated by operating the switches under different angles of the source.Finally,according to the results of simulation and theoretical analysis,a best choice(i.e.angles of the source) to switch on capacitor banks is proposed.In this case the over-voltage on the capacitor will be limited to lowest.     

基于局部特征的复杂曲面零件行切加工

提出了一种新的复杂曲面行切加工算法.该算法利用短程线的特性,根据曲面的局部特征自适应地调整相邻刀位轨迹线之间的间距,实现了刀位轨迹在曲面上的等距分布.与现有的曲面行切算法相比,在相同精度条件下,采用该算法加工复杂曲面,走刀路径可以缩短10％以上,有效地提高了加工效率和质量.     

Hermite interpolation of scattered data based on the assistant surface

An assistant surface was constructed on the base of boundary that being automatically extracted from the scattered data. The parameters of every data point corresponding to the assistant surface and their applied fields were calculated respectively. In every applied region, a surface patch was constructed by a special Hermite interpolation. The final surface can be obtained by a piecewise bicubic Hermite interpolation in the aggregate of applied regions of metrical data. This method avoids the triangulation problem. Numerical results indicate that it is efficient and accurate.