励磁装置是水轮发电机组的重要控制设备之一,其性能的优劣直接关系到机组自身和 电力系统的安全稳定运行。提高励磁装置的控制性能,对于改善电力系统静态、暂态及动 态稳定性相当重要,并且可以提高水轮发电机组的设备利用率。本文针对安康水电站励磁 装置陈旧落后的现状,对所存在的问题进行了较为深入的分析讨论,提出了改造原旧励磁 装置的必要性。安康水电站原励磁装置严重制约已实施改造的微机调速、微机保护、计算 机监控作用的发挥,已成为进一步提高电厂整体自动化水平的瓶颈。在广泛调查分析国内 目前先进励磁装置及其工作性能的基础上,提出了适合安康水电站机组励磁系统改造的最 佳方案一一双微机全控桥式自并励磁系统。新方案的实施,将充分发挥安康水电站在西北 电网中承担调峰、调频的重要作用。 为了充分利用设备,保持原机组的机械旋转系统状态,现将励磁系统改造后空余出的 交流励磁机改为同轴运转的副发电机,增加整体机组的工作容量。本文对副发电机结构参 数、电磁谐波引起的振动和推力轴承强度等进行了详细的计算。并对副发电机与主发电机 可能运行方案做了深入的分析研究。当副发电机与主发电机分别运行于两个独立电网时, 由于机组转速取决于主发电机所在的大电网,副发电机将承担其所在电网的全部变动负荷。 因此,副发电机所在的电网负荷容量不要超过副发电机的容量。当副发电机与主发电机运 行于同一电网时,二者不仅有电磁联系,而且有机械联系。在副发电机或主发电机励磁发 生变化时,不但会使机组的无功发生变化,而且会在主、副发电机之间发生有功功率的重 新分配。主、副发电机磁极中心线与系统初相角前后不同,将使主、副发电机并入电网的 顺序不同。由于主、副发电机容量差别很大,并考虑到机械系统的稳定性,应保证主发电 机带负荷优先原则。本文还对副发电机改造方案的投资效益进行了分析比较论证。 关键词:安康水电站,水轮发电机组,励磁装置,静态与暂态稳定,副发电机,技术改造 )TheResearchontheSchemeofChang1ngA1ternat1veExcitation Sett1ng1ntoSubs1d1aryGeneratorforAnKangHydroPowerP1ant 、心办妙户吩ABSTRACT,叱J哟““ Exeitationsetting15oneoftheimPortanteontroldevieesforhydraulie turbinegeneratorunit.ItsPerformanee15akeyfaetor贾hiehi.Paetdireetlyon thesafetyandstabilityrunningoftheunititselfandPowersystem.Theaugment ofexeitationsetting’5eontrolPerformanee15fairlyimPortanttoimProvethe statie,transientanddynamiestabilityofPowersystem,andenhaneethesetting’s utilizationratingofthehydraulieturbinegeneratorunit.ThisPaPeraimsatthe behindstatusinquoofexeitationsettinginAN_KANGhydroPowerPlant,analyzes andtalksaboutitsquestionthoroughly,andPresentstheneeessarityoftheold exeitationsetting’5alteration.Theoldexeitationsettinginan_kanghydroPower PlantrestrietsthedeveloPmentofthemieroeomPuterregulatorofsPeed, mieroeomputerProteetionandtheeomputersupervisorandeontrolthathasaltered, hasbeeomeabottleneekinimProvingthelevelofautomationinPowerPlant.Based onalargenumberofinvestigationsandanalysisofexeitationsettingsandtheir Performaneeinhomeland,thisPaPerPresentsabetterProjeet,whiehadaPtstothe alterationofexeitationsysteminan_kanghydroPo贾erPlant一exeitationsystemon doublemieroeomPuter.TheimPlementationofnewProjeetwillfairlyPlaya imPortantroleinregulatingPeakandfrequeneyinnorthwestPowersystem. Inordertomakethefulluseofthefaeilitytomaintainthemaehinerotating system,thealternativeexeitationsetting,份hiehremainsbyalteringthe exeitationsetting,15ehangedintosubsidiarygeneratorrunningonthesameshaft. 卫And1teanenhaneetheworkeaPaeityofthewholeunit.ThisPaPergivethedetailed ealeulationsinstruetureParameterofsubsidiarygenerator,thevibrationarises bydatromagnetismharmoniewaveandintensityofthrustbearing.ThisPaperalso 9ivestheanalysisandresearehesthepossibleoperatingsehemeinmaingenerator andsubsidiarygenerator.ThesubsidiarygeneratoroutPutdePendsontheloadof powersystemwhenthemaingeneratorandsubsidiarygeneratoroperatinginseparate Powersystem.Itnotonlyhaseleetromagnetismbutalsohasmeehanismeonduetion asthemaingeneratorandaeeessorygeneratoroperatinginthesamepowersystem. Whenthegeneratorexeitationhasbeenehanged,thereaetivepowereouldbe variationandtheaetivePowereouldberebuildinthemaingeneratorandsubsidiary generator.ThevibrationofmagnetismPoleeenterinmainandsubsidiarygenerator eouldbededueedtothedifferentorderwhenthegeneratorPutintopowersystem. Ke汗ords:AN_KANGhydropowerstation,hydraulieturbinegeneratorunit, exeitationsetting,statieandtransientstability,subsidiarygenerator, teehniquealteration目录 前言.........一”............~........~.”二~...............”.....”~....一一...”.....................................“...........一1 1.励磁系统技术改造的必要性.“二~一“二~.”二_~..…~…~”~...“~....~~..”..............~......................~.......~.. 1.1机组及励磁系统的参数.....“...............“.......“.............................~.“...~...”...........................2 1.2现有励磁系统对稳定不利.........一~…~.~~~~一...~~....~....“.~.........一................................3 1.3现有励磁系统选型落后、设备可靠性差............一........................................................~........ 2.自并励静止可控硅励磁系统的工作原理..........一..~.....................~............~...................“...........”...........一9 2 . 1三相桥式全控桥整流电路..一......................................................................................................10 2 . 2励磁调节器...................................................................................~...................一......................10 2.2.1基本特性与框图......“........“.........“..…“...................….................................fl 2.2.2发电机励磁控制系统静态特性.…“..…“一~.~~一“~…”.“.~...~..~................11 2.2.3辅助控制...................一..一~…~...一..........................................、........一...~一~13 2.2.4数字式微机型励磁调节器.........................................一...................................................巧 3.励磁自动控制系统对电力系统稳定的影响............一.….....….…~............”......”.....”............................一18 3.1功角稳定.............一.....一..........”..…,............…..…“....................”~..........................一18 3.2频率稳定....”....”...一..........”....”.......”…~..…”~...........~..~.................~.一....一..一18 33电压稳定....~..................一...~~..一“...........~...一..…~.....“..~一“..一...~.................一...19 4.励磁系统技改方案的建议..”......….…”二~........................................”.............”...................................一20 4.1励磁变压器的选择.…,....................~…“.......”.…~”........一.....................................一...20 4.2可控硅整流装置...‘.....一.........”............”...............一.................一........一........................21 4.3双微机调节器.一.~.…~~~一”“二~二“....”.”~“~一~~.....一“.~二”~一~”一.~.....~..一...........一l 4.4起励回路..........一....,..…~~..…~......….…~…”......….…”二~”.”....一~........-......................一23 4.5灭磁装置(包括转子过电压保护).......................一...................…二~.....................一........23 5.交流励磁机改付发电机可行性研究.............~....一......一...........“....~..........一.~..................25 5.1情况介绍一~~一~一~一~二~…~.~.…~:.~~~~~“.~~~~一~一一“.~.~~.~一~:.~一~一~..…~.~.~一25 5.2大机主要参数及结构特点..…~.....一~.”“一......................一.......~......~.”......一~........一25 5.3小机电磁方案分析比较.””.......”…“.“....”二~.”…““.......一...一~.”~......................~..一26 5.4小机主要部件强度分析..........“~…~.“..一....一一~~.…~~二“.....-.........一..…”...........................28 5 . 5对大机的影响分析...........................一...............’..............................“.“~.....~二~.......29 5.5.1大机上机架核算.~.........“~.~.............~.~二~“.........~..…”~..............一.........29 5.5.2大机推力轴承核算.”.............一...........~~....“.“..........................................29 5.5.3对电厂通风散热的影响.............一~…~~…~......一””二~二~......一.~二~.............一305 . 6小机对电网的影响分析........一................一.”..30 5.6.1电压谐波因数及电压波形畸变率.......................................................................30 5.6.2小机与大机并入同一电网…,‘............~…~..,30 5.6.3小机并入与大机完全独立的电网....