干式空心电抗器匝间电弧性短路故障特征提取及诊断方法研究

针对干式空心电抗器早期匝间短路故障,通过分析电抗器匝间电弧性短路过程中的状态参数变化规律,提出了基于时变参数模型的电抗器故障特征提取及诊断方法。首先建立了基于Mayr电弧模型的电抗器匝间短路故障的时变电路模型,并利用傅里叶变换分析了故障电抗器等效电感的频谱特性,发现其等效电感不再恒定而是存在周期性振荡。然后利用时变电路状态方程求解方法,分析在工频激励下故障电抗器输出电流的转移解、零状态响应及频谱特性,证明在匝间电弧的周期性短路过程中,故障电抗器输出电流中将激发出特定次数的谐波分量,分析电流谐波特性可对干式空心电抗器匝间短路故障进行诊断。通过对一起电抗器故障的电流互感器（CT）和电压互感器（PT）录波数据进行求解和分析,验证了本文提出的故障特征提取及诊断方法的可行性和有效性。     

新能源-质子交换膜电解槽电制氢容量双层规划模型研究

新能源电制氢是实现“2060碳中和”的关键技术之一。然而,新能源出力具有随机性,且制氢关键设备——质子交换膜（PEM）电解槽投资成本与运行成本高,因此如何为出力功率随机的新能源电站配置兼顾新能源弃电率与制氢系统经济性的PEM制氢系统具有重要意义。以风电制氢为例,首先提出随机波动输入下PEM电制氢系统全寿命周期的成本与收入模型,并以总收入、投资回收期与内部收益率为评估指标支撑系统的经济分析;基于此,针对“风电+PEM电制氢”系统,提出3种双层规划模型,上层模型分别以PEM电制氢系统全寿命周期总成本最小、总收入最大与内部收益率最大作为上层优化模型的目标函数,下层的优化目标为风电场的弃电率最小,并采用MATLAB遗传算法工具箱求解优化模型;最后,以某实际风力发电场为例,验证所提双层规划模型与风电制氢的有效性与经济可行性。     

SCAL型间接空冷系统循环水中溶氧量变化规律及其对pH值间接影响

表面式换热器铝制散热器（SCAL）型间接空冷（间冷）机组已经成为解决我国北方富煤贫水地区发电的有效措施,该机组SCAL型间冷系统稳定运行过程中常出现循环水pH值异常升高的现象。由于系统内散热器采用铝材质,pH值异常升高会破坏铝管表面氧化膜,导致散热器腐蚀甚至泄漏,因此循环水pH值异常升高是该系统运行的难题。通过对SCAL型间冷系统结构的分析、水质调研,分析了系统中的动态变量,通过理论计算和工业试验验证对该问题进行了深入研究。结果表明:SCAL型间冷系统在运行期间基本处于密闭状态,外界氧气难以扩散进入,系统循环水中溶解氧的来源为系统运行前除盐水中溶解的氧气;碳钢的腐蚀反应是系统中溶解氧主要的消耗方式;溶氧量变化改变了碳钢腐蚀产物的类型,当系统中溶氧量较低时,碳钢腐蚀生成的Fe(OH)2具有较大的溶度积,能够导致循环水pH值升高。     

生物质直燃发电大气污染物超低排放技术路线分析

总结了生物质燃料与煤的元素含量的差异,分析了生物质锅炉积灰、结渣、腐蚀的机理,梳理了生物质锅炉的烟气特点,并对选择性非催化还原脱硝技术、选择性催化还原脱硝技术、湿法脱硫技术在生物质电厂应用的局限性进行了讨论和总结。结果表明:固态高分子脱硝和催化剂脱硝脱硫均需特殊催化剂或脱硝剂,属于专利产品,运行成本高;氧化脱硝技术属于氧化吸收反应,产生易溶于水的硝酸盐,部分地区禁止采用该技术;陶瓷催化滤管一体化脱除技术运行维护简单,锅炉过氧燃烧可提高燃烧效率,延长空气预热器使用寿命,而且没有脱硫废水、烟囱防腐、白色烟羽等相关问题,适用于生物质锅炉硫、尘、硝超低排放。     

旁路蒸发塔氯离子迁移模型及固态蒸发产物利用探讨

目前,国家鼓励采用烟气蒸发技术处理燃煤电厂脱硫废水以实现废水零排放。旁路蒸发塔工艺使用300 ℃以上热烟气干燥废水,废水中含有较高浓度的Cl–,蒸发过程中一部分Cl–生成氯化氢进入气相,剩余Cl–与其他离子形成结晶盐即固态蒸发产物,其与粉煤灰混合可能会导致Cl–超标,影响粉煤灰的综合利用。使用状态方程法计算Cl–气固相间分配量,建立蒸发塔的Cl–迁移模型。结合某电厂实际数据,利用模型计算出固态蒸发产物的含氯量,结果表明:固态蒸发产物不属于危险废物,但含氯量较高,会对利用固态蒸发产物生产建材产品产生影响,推荐使用高温陶瓷过滤器或小型电除尘器单独收集固态蒸发产物,并可将收集的固态蒸发产物应用于生产混凝土、免烧结砖,或矿井、公路路基、台背等回填工程中。     

EFFECTS OF SPECIFIED BLANK SIZE ON BODY WRINKLING DURING HYDRODYNAMIC DEEP DRAWING OF TAPERED RECTANGULAR BOX

1.~nonHydridapawhcdeepdrawing(HDD)belongstothefieldofsheetmetalfoeingandcanbeaPPliedinthefieldofautomotive,aerospace,drilitaryindustryetc.Ithasbeenrecognizedwidelyintheworld["'j.Fig.Ishowsitsprinciple:TheliqUidthatisfilledinthe~ngdiecavitywillbepressedwhenthepunchgoesdownsothattheeffectoffrictionkeepingandoverflowlubricatingcanbeformed,astherestilt,thefoeinglicitofsheetmetalwillbeimprovedareailvandthegualitVofthefinishedpartswillbeup~ed.BecauseofmanyadvantagesofHDDprocees,ithasbeenwidelys…     

EFFECT OF ALLOY ELEMENTS ON QUASIEQUILIBRIUM MICROSTRUCTURE IN Fe-Mn-Ni-Cr STEELS

The microstructures of Fe-Mn-Ni-Cr steels with medium carbon and the effect of alloy ele-ments on them have been investigated by means of X-ray diffraction quantitative phase ana-lyses,metallography and hardness tests.The volume fraction of martensite in steels quenchedat 1100℃ can be expressed as:f_M~(1100)=162.643-15.482Mn-7.36Ni-4.286(Cr+Mo+V)Based on this expression,the quasi-equilibrium microstructure diagram has been obtained.Itis shown that the effect of Mn on the austenite stability is greater than that of Ni.The equiva-lent [Ni]=2.104Mn+Ni and equivalent [Cr]=Cr+Mo+V.The driving force for martensite transformation at M_s point has been calculated to hedrastically decreased by element Mn.     

Advances in the research of nitrogen containing stainless steels

The current status of nitrogen containing stainless steels at home and aboard has been introduced. The function and existing forms of nitrogen in the stainless steels, influence of nitrogen on mechanical properties and anti-corrosion properties as well as the application of nitrogen containing cast stainless steels were discussed in this paper. It is clear that nitrogen will be a potential and important alloying element in stainless steels. And Argon Oxygen Decarbonization (AOD) refining can provide an advanced manufacture process for nitrogen containing stainless steels with ultra-low- carbon and high cleanliness.     

4-methoxy-2,6-bis(3,5-dimethylpyrazoyl)-1,3,5-triazine modified carbon paste electrode for trace Cu(Ⅱ) determination by differential pulse volt-ammetry

A differential pulse voltammetric method was developed for the sensitive and selective determination of Cu(Ⅱ) at 4-methoxy-2,6-bis(3,5-dimethylpyrazoyl)-l,3,5-triazine modified carbon paste electrode in 0.05 mol/L KHC8H4O4 solution (pH = 4.02). The oxidation peak of Cu(Ⅱ) was observed at 0.065 V(vs Ag/AgCl) by scanning the potential in positive direc-tion. The analysis procedure consisted of an open circuit accumulation step in stirred sample solution. It was followed by medium exchange to a clean solution and subsequently an anodic potential scan was affected to obtain the voltammetric peak. The current was proportional to the concentration of the Cu(Ⅱ) ion in a range of 1× 10-7-1×10-4 mol/L for 6 min accumulation; the most of metal ions did not interfere with the determination. The developed method was applied to Cu(Ⅱ) determination in coal-ash sample, the results agreed with that of atomic adsorption spectroscopy(AAS).     

Water modeling of molten steel flow in a multi-strand tundish with gas blowing

Fluid flow characteristics in a four-strand tundish with gas blowing were studied by water modeling experiments.It is found that gas blowing can greatly improve the flow characteristics in the tundish with a turbulence inhibitor.It dramatically increases the peak concentration time,and greatly decreases the dead volume,and reduces the minimum residence time.The gas blowing location,gas flow rate,and porous plug area greatly influence the flow characteristics in the tundish;the gas blowing location near t...