综合管廊电气工程的相关问题研究

城市综合管廊是现代城市建设的重要综合系统,其电气工程设计工作需要关注供电电源、接地系统、照明设计、电气设备防潮、电缆敷设等关键环节。     

不同添加剂对AgSnO2In2O3触头材料电性能的影响

采用内氧化法工艺制备了不含添加剂及分别含添加剂CuO或TeO2的3种AgSnO2In2O3触头材料。应用模拟继电器试验设备检测了这3种材料在AC230 V、25 A阻性负载条件下的电寿命、熔焊力、电弧能量、燃弧时间、质量侵蚀率等相关电性能参数,并对检测结果及试验后铆钉触头样品进行了分析。研究发现:与不含添加剂的AgSnO2In2O3材料相比,添加剂CuO对材料的电寿命影响不大,而添加剂TeO2明显提高了材料的电寿命;含添加剂的两种材料的熔焊力和电弧能量均有了不同程度的降低,但它们的质量侵蚀率却明显增加。     

连续通电条件下触点接触电阻劣化的初步分析

电器长期通电后可使触点表面劣化,具体体现为接触电阻稳定增大、无规律增大、周期性变化、瞬时变化等电接触失效形式。本文以银镍触点材料为例,试验研究了接触压力、通电时间和通电电流对接触电阻的影响,并分析了接触电阻劣化失效的物理机制。     

一起110kV电容式电压互感器缺陷分析

电容式电压互感器(capacitor voltage transformer,CVT),是变电站的重要设备,主要用来测量线路电压,为二次设备提供电源等。通过对一起某变电站110 kV电容式电压互感器异常发热缺陷分析,结合电气试验、油色谱检测等,对缺陷部位和原因进行诊断,并提出了相应的防范措施。     

Synergistic Effect of PVDF-Coated PCL-TCP Scaffolds and Pulsed Electromagnetic Field on Osteogenesis

Bone exhibits piezoelectric properties. Thus, electrical stimulations such as pulsed electromagnetic fields (PEMFs) and stimuli-responsive piezoelectric properties of scaffolds have been investigated separately to evaluate their efficacy in supporting osteogenesis. However, current understanding of cells responding under the combined influence of PEMF and piezoelectric properties in scaffolds is still lacking. Therefore, in this study, we fabricated piezoelectric scaffolds by functionalization of polycaprolactone-tricalcium phosphate (PCL-TCP) films with a polyvinylidene fluoride (PVDF) coating that is self-polarized by a modified breath-figure technique. The osteoinductive properties of these PVDF-coated PCL-TCP films on MC3T3-E1 cells were studied under the stimulation of PEMF. Piezoelectric and ferroelectric characterization demonstrated that scaffolds with piezoelectric coefficient d₃₃ = −1.2 pC/N were obtained at a powder dissolution temperature of 100 °C and coating relative humidity (RH) of 56%. DNA quantification showed that cell proliferation was significantly enhanced by PEMF as low as 0.6 mT and 50 Hz. Hydroxyapatite staining showed that cell mineralization was significantly enhanced by incorporation of PVDF coating. Gene expression study showed that the combination of PEMF and PVDF coating promoted late osteogenic gene expression marker most significantly. Collectively, our results suggest that the synergistic effects of PEMF and piezoelectric scaffolds on osteogenesis provide a promising alternative strategy for electrically augmented osteoinduction. The piezoelectric response of PVDF by PEMF, which could provide mechanical strain, is particularly interesting as it could deliver local mechanical stimulation to osteogenic cells using PEMF.     

交流滤波器避雷器电气特性分析中不同仿真模型的影响

交流滤波器是直流输电系统的重要设备。主要分析仿真模型对交流滤波器用避雷器电气特性（过电压、电流和吸收能量）的影响,基于PSCAD电磁仿真程序,开展滤波器投入和交流滤波器母线接地故障下的建模及仿真计算。仿真结果表明：在交流滤波器投入工况下,采用单个滤波器大组模型（模型1）进行仿真时,在运滤波器的避雷器不动作,与实际情况不符;在滤波器投入及滤波器母线接地故障下,完整参数模型（模型3）中各组滤波器用避雷器过电压比原系统模型（模型2）和模型1降低可达21%,电流降低可达53%,但吸收能量升高可达56%。因此,若在绝缘设计中不采用完整参数模型,避雷器电压电流设计值会偏大,能量设计值会偏小,同时会在滤波器投入工况下忽略同大组其他交流滤波器的避雷器动作情况。     

AlCl3-BMIC离子液体的电导率

研究AlCl3-BMIC(氯化-1-甲基-3-丁基咪唑)离子液体电导率与温度、组分之间的关系。结果表明:当离子液体中AlCl3的摩尔分数x(AlCl3)<0.667时,离子液体的电导率随着x(AlCl3)的增加而增大;但在0.6670.5的路易斯酸性区域,x(AlCl3)对温度系数α、β的影响均不明显。     

中小电机新能效等级对无取向电工钢需求的影响

电机新能效等级标准的实施,对硅钢产品提出了更高的要求。本文结合中小电机、无取向电工钢的发展,分析了电机的损耗与硅钢性能的关系,并提出了新能效等级标准实施后对无取向电工钢的需求预测。     

浅谈无底层取向电工钢的多种应用

介绍了国内无底层取向电工钢生产技术水平、产量和用途,简述了无底层取向电工钢作为取向电工钢超/极薄带母料及应用于制作大型发电机组铁心、风电等电机铁心和变压器铁心等的情况。     

锡或锑在无取向电工钢中的研究进展

近年来,在节能减排背景之下,国内外众多研究者对无取向电工钢磁性能的提升做了大量研究。为了探索无取向电工钢磁性能提升的方法,对锡或锑对无取向电工钢磁性能的作用机制(晶粒尺寸和晶体织构的控制)进行分析。基于该作用机制,介绍锡或锑的添加对无取向电工钢磁性能的影响。经研究发现,适量的锡或锑在晶界偏聚,不会阻碍晶界的移动并且致使晶粒尺寸降低;与此同时,锡或锑在晶界偏聚不仅抑制{111}织构在原始晶界处形核及生长,还降低(100)晶粒表面能,促进(100)晶粒生长。因此,适量添加锡或锑,可使无取向电工钢铁损下降、磁感提升。最后结合生产工艺,建议无取向电工钢的研究方向应为稀土含量对高牌号无取向硅钢夹杂物尺寸和数量分布的影响,锡或锑的添加量和常化工艺参数(常化时间、常化温度)对常化晶粒尺寸的影响。