大容量风电并网电网故障对潮流的影响

风力发电作为清洁环保型能源得到了迅猛发展,但大规模风电场接入电网对电力系统安全稳定运行、保护设置及电能质量等产生了影响。以赤峰电网实际发生的电网故障为例,通过综合分析程序对故障期间的电网工况进行建模仿真,分析故障情况下风电突变对电网潮流的影响。     

DG252型整体卡瓦封隔器

<正> DG252型整体卡瓦封隔器,是近年来大港油田井下作业指挥部攻关队(现为采油工艺研究所)研制出的一种新型封隔器,它是采用从国外引进的一种独特的整体卡瓦,并结合两种不同的座封换向机构,设计了DG252-1型和DG252-2型封隔器。     

Effect of electromigration and isothermal aging on interfacial microstructure and tensile fracture behavior of SAC305/Cu solder joint

The Cu/Sn-3.OAg-0.5Cu/Cu butting solder joints were fabricated to investigate the evolution of the interfacial intermetallic compound(IMC) and the degradation of the tensile strength of solder joints under the effect of electromigration(EM) and aging processes.Scanning electron microscopy(SEM) results indicated that the Cu_6Sn_5 interfacial IMC presented obvious asymmetrical growth with the increase of EM time under current density of 1.78×10~4 A/cm~2 at 100℃,and the growth of anodic IMC presented a parabolic relationship with time while the cathodic IMC got thinner gradually.However,as for aging samples at 100℃ without current stressing,the Cu_6Sn_5 IMC presented a symmetrical growth with a slower rate than the anodic IMC of EM samples.The tensile results indicated that the tensile strength of the solder joints under current stress declined more drastic with time than the aging samples,and the fracture mode transformed from ductile fracture to brittle fracture quickly while the fracture mode of aging samples transformed from cup-cone shaped fracture to microporous gathering fracture in a slow way.     

温度梯度作用下的Ni/Sn/Cu焊点界面反应分析

采用Ni/Sn/Cu互连焊点作为研究对象,在不涉及电迁移效应条件下,设置温度梯度为TG=1 046℃/cm,研究在热迁移作用下镍为热端、铜为冷端时界面金属间化合物(intermetallic compound,简称IMC)的显微组织变化. 结果表明,随着热迁移加载时间的增加,冷、热两端界面IMC的厚度都增加,但冷端界面IMC的生长速率大于热端.EDS分析表明,界面IMC是(Cu,Ni)6Sn5相,并且热端IMC中的Ni元素含量高于冷端. 另外,在冷端的界面(Cu,Ni)6Sn5相中观察到大量的空洞,且在(Cu,Ni)6Sn5/Cu界面之间没有观察到Cu3Sn.     

鄂尔多斯北区钻具失效的特点及预防

鄂尔多斯北区油气勘探开发进入了一个试验开发新阶段。在钻井实践中,发生了大量的钻具失效事故,极大地影响了钻井速度。通过对鄂尔多斯北区钻真失效事故的数据统计,对钻具失效形式进行分类,分析了钻具失效的主要机理;提出了预防和减少钻具失效的技术措施。现场应用后,大幅度减少了钻具失效事故,对今后在该地区钻井施工有一定的指导作用。