宝鸡换流站阀厅电气连接及金具设计特点

直流换流站阀厅设备布置、电气连接以及金具设计是保证阀厅电气安全净距,控制电晕及场强,实现换流站安全可靠运行的重要环节。分析了完全采用国产化设备的±500kV宝鸡换流站阀厅电气设备选型、布置及一次连接的设计特点。在此基础上,根据阀厅内电气连接的特殊要求,详细介绍阀厅内金具的设计方案及特点,并对阀厅电气设计和建设管理经验进行了总结。

高地震烈度地区特高压换流站阀厅电气布置及联接设计

阀厅的电气设计是整个换流站设计的重点和难点,特别是对于高地震烈度地区特高压换流站,需要在常规电气布置和连接方案的基础上进行相应的改进和优化,以适应高地震烈度地区阀厅电气设备抗震的需要。±800 kV新松换流站站址位于8度地震区,电气设备和布置连接按照9度(0. 4 g)设防设计。在分析新松换流阀厅内电气设备抗震计算结果的基础上,对阀厅的电气布置和连接方案进行了优化。在兼顾电气特性和机械特性的基础上,采用水平Z型和垂直Z型管母金具等特殊金具连接方案,对阀厅内部关键电气回路进行了抗震解耦,保证了阀厅内电气设备在地震工况下仍可安全运行。

电网舞动灾害应对技术体系研究综述

中国电网结构复杂,线路分布广泛,近年来受气候异常变化影响,大范围、长时间舞动导致的机械、电气故障频发。尤其是2007年以来,对线路运行影响较大的舞动灾害天气过程呈多发态势。统计数据显示,覆冰舞动已经成为导致线路故障停运的首要原因。传统舞动防治技术手段大都以舞动诱发过程为主要防治对象,基于“避、抗、防、测”基本原则,构建了电网舞动灾害应对技术体系,主要防治手段包括绘制舞动分布图,制定防舞设计标准,提出装置设计、检测、应用和评价方案等。经过多年的完善,现有技术体系体现出了较好的防范和治理效果,但在舞动发生期间却不具备任何实用性和可操作性。文中针对现有电网舞动灾害应对技术体系的优势、不足和针对性的完善措施,以及近期非线性动力减振、舞动机理、人工智能等相关领域研究成果进行总结介绍和综述,并指出今后可能实现更好舞动应对效果的技术领域和研究方向,力图为电网防灾减灾和线路运维工作提供借鉴和参考。

架空光缆金具的设计和应用特征

针对电力、电信领域应用的架空光缆,研究分析直接与光缆接触、实现固定的金具。根据研发进展,介绍了不同种类架空光缆的设计原理和应用特点,着重分析了自承式电力架空光缆金具、自承式非电力架空光缆金具和FTTH室外架空光缆金具的主要类型和技术要求。架空光缆金具是为架空光缆服务的,只有金具的设计原理、应用特点与光缆性能相互匹配,才能将光缆安全地固定住,同时起到保护光纤的作用,且有利于安装和维护工作。

FEM simulation of aluminum extrusion process in porthole die with pockets

In order to investigate the effects of pockets in the porthole die on the metal flow,temperature at the die bearing exit and the extrusion load were contrasted with the traditional die design without the pockets in the lower die.Two different multi-hole porthole dies with and without pockets in lower die were designed.And the extrusion process was simulated based on the commercial software DEFORM-3D.The simulation results show that the pockets could be used to effectively adjust the metal flow and especially benefit to the metal flow under the legs.In addition,the maximum temperature at the die bearing and the peak extrusion load decrease,which indicates the possibility of increasing the extrusion speed and productivity.

Fabrication of fine-grained,high strength and toughness Mg alloy by extrusion−shearing process

A novel extrusion-shearing(ES) composite process was designed to fabricate fine-grained, high strength and tough magnesium alloy. The structural parameters of an ES die were optimized by conducting an orthogonal simulation experiment using finite element software Deform-3D, and Mg-3 Zn-0.6 Ca-0.6 Zr(ZXK310) alloy was processed using the ES die. The results show that the optimized structural parameters of ES die are extrusion angle(α) of 90°, extrusion section height(h) of 15 mm and inner fillet radius(r) of 10 mm. After ES at an extrusion temperature and a die temperature of 350 °C, ZXK310 alloy exhibited good ES forming ability, and obvious dynamic recrystallization occurred in the forming area. The grain size decreased from 1.42 μm of extrusion area to 0.85 μm of the forming area. Owing to the pinning of second phase and formation of ultrafine grains, the tensile strength, yield strength and elongation of alloy reached 362 MPa, 289 MPa and 21.7%, respectively.

Research on the Seebeck effect in efficient turning process and improving tool life

In this paper, for the tool wear problem of the cutting process, the study on improving tool life has been done through the analysis of the Seebeck effect in the efficient turning process. The generation principle of the self-excited electric current in the cutting process is studied, and also its effect on the life of the turning cutter is studied, so as to reveal the mechanism of the self-excited electric current accelerating the wear of cutting tools. The study results show that the self-excited electric current which is generated during the cutting process is one of the main reasons that cause both the accelerated hardening and the low life of cutting tools to happen. Thus, if the generation of self-excited current is avoided and reduced, the cutting performance of cutting tools can be effectively improved, so to improve the tool life. The study can provide the anti-friction and anti-wear theory basis for the design of the efficient cutting tools.