简介:摘要:低压交流电源作为变电站的站用电,所起的作用非常重要,应引起我们高度重视,交流失压会造成全站失电,变压器风冷全停,因此,需要我们不断完善低压系统,使之更加可靠。[关键词]低压交流可靠性变压器风冷系统风冷全停一、重要性分析目前,发电厂和变电站一般采用直流操作电源,因为直流电能可以通过蓄电池存储,可以看成与发电厂和变电所一次系统无关的独立电源,在发电厂和变电所出现故障甚至交流电源完全消失的情况下,蓄电池直流系统仍能可靠工作,维持电压恒定,因此它具有很高的供电可靠性。此外,由于蓄电池电压平稳,容量较大,因此可以提供断路器合闸时较大的短路冲击电流和正常负荷起始冲击电流,并可以作为事故保安负荷的备用电源……
简介:NoImpaseforChina’sDevelopmentJianSongToday,Chinahasamorethan1.2bilionpeople,about22%oftheworld’stotal,whoarefedwiththegrainpr...
简介:IncreasinglyaWoman'sDisease¥ZhangKonglaiandWangYingAIDSisadeadlysexuallytransmitteddiseasecausedbythehumanimmuno-deficiencyvi...
简介:CHINA'SAGENDA21CHINA'SAGENDA21WhitePaperonChina'sPopulation,EnvironmentandDevelopmentinthe21stCenturyThefollowingareexcerptsf...
简介:Tibet’sPopulationandTibetanPopulationGuoDapingTheTibetannationality,oneofChina’smajorethnicgroups,hasinhabitedontheQinghaiTi...
简介:TasksforChina’sAgingProgrammeTheobjectivesofChina’sagingprogrammeareto“provideeconomicsupport,medicalandhealthcareservicesand...
简介:China'smalemarriagesqueezeanditspotentialconsequencehaveattractedmuchattentionandgivenrisetodebate,butmoststudiescontributethissqueezetosexstructureandneglecttheagestructure,andsomestudiesuseflawedmethodtostudythecontributionofagestructureinthissqueeze.InthispaperwedevelopanindicatorofSpousalSexRatio(SSR)andapplyadecompositionmethodintoageandsexstructure.BasedonthedatafromChina's2010censusandprojection,wepredictthatfrom2010to2020,theagestructurewillbethedominantfactorforChina'smalemarriagesqueeze,andfrom2020to2034,thecontributionofsexstructurewillbeincreasing,whereasthatofagestructurewillbedecreasing.From2034to2045,China'smalemarriagesqueezewillmainlyfromimbalancedsexstructure,andtheagestructurewillcontributelittleornegativelytoChina'smalemarriagesqueeze.