变电站站用电系统接线方式比较及其运行维护分析

讨论了220 k V及以下变电站低压交直流系统的常见接线方式,对几种特殊接线方式进行了总结,分析了它们的特点及其在日常运行维护与操作过程中需要注意的事项,并展望了智能变电站交直流一体化电源的发展趋势,为变电站低压交直流系统的运行维护提供参考。     

智能变电站网络通信异常的分析

智能变电站网络结构分为站控层、间隔层和过程层。网络通信异常会使变电站失去监控信号或使保护装置失去保护作用。本文分析了两种网络通信故障,总结了他们产生的原因,提供了解决方法,为今后智能站的运行维护提供参考。     

Stress and Thermal Analysis of the In-Vessel Resonant Magnetic Perturbation Coils on the J-TEXT Tokamak

A set of four in-vessel saddle coils was designed to generate a helical field on the J-TEXT tokamak to study the influences of the external perturbation field on plasma. The coils are fed with alternating current up to 10 kA at frequency up to 10 kHz. Due to the special structure, complex thermal environment and limited space in the vacuum chamber, it is very important to make sure that the coils will not be damaged when undergoing the huge electromagnetic forces in the strong toroidal field, and that their temperatures don’t rise too much and destroy the insulation. A 3D finite element model is developed in this paper using the ANSYS code, stresses are analyzed to find the worst condition, and a mounting method is then established. The results of the stress and modal analyses show that the mounting method meets the strength requirements. Finally, a thermal analysis is performed to study the cooling process and the temperature distribution of the coils.