摘要PAGE\*MERGEFORMAT69摘要变电站是电力系统的重要组成部分，它直接影响整个电力系统的安全与经济运行，是联系发电厂和用户的中间环节，起着变换和分配电能的作用。电气主接线是发电厂变电所的主要环节，电气主接线的拟定直接关系着全厂（所）电气设备的选择、配电装置的布置等，是变电站电气部分投资大小的决定性因素。本次设计建设一座110KV降压变电站，首先，根据主接线的经济可靠、运行灵活的要求选择各个电压等级的接线方式，在技术方面和经济方面进行比较，选取灵活的最优接线方式。其次进行短路电流计算，根据各短路点计算出各点短路稳态电流和短路冲击电流。然后，根据各电压等级的额定电压和最大持续工作电流进行设备选择，然后进行校验。最后作出平面布置图和防雷保护设计。关键词：变电站主接线短路计算电气设备选择ABSTRACTElectricitysubstationisanimportantcomponentofthesystem,itdirectlyaffectthepowersystemsecurityandeconomicoperationofpowerplantsarelinkedandusersofintermediatelinks,transformationanddistributionofpowerplaysarole.Themasterdocumentofsubstationisthemainlinkinthemainelectricalwiring,whichdirectlyrelatedtothedevelopmentofthewholeplant(subtations)thechoiceofelectricalequipment,powerdistributiondevicesandsoon,suchasthearrangementispartoftheinvestmentthesizeoftheelectricalsubstationdecisivefactor.Thedesignoftheconstructionofa110KVstep-downsubstation.Firstofall,accordingtothemainterminaloftheeconomicandreliableoperationofallflexibilitytochoosetheconnectionmodevoltage,inthetechnicalaspectsandeconomicaspectsofcomparison,theflexibilitytoselecttheoptimumconnectionmode.Second,Ihavetocarryoutshort-circuitcurrentcalculation,accordingtopointouttheshort-circuitshort-circuitalltheshort-circuitcurrentandtheimpactofsteady-statecurrent.Then,accordingtothevoltagelevelofratedvoltageandmaximumcontinuousoperatingcurrentequipmentchoice,andthenproceedtocheck.Tomakeafinalfloorplananddesignoflightningprotection.Keyword：subtationmasterdocumentcalculationofshortcircuitelectricequipmentselection目录目录TOC\o"1-3"\h\z\uHYPERLINK\l"_Toc165779899"引言PAGEREF_Toc165779899\h1HYPERLINK\l"_Toc165779900"1电力系统分析及变电站总体分析PAGEREF_Toc165779900\h2HYPERLINK\l"_Toc165779901"1.1电力系统分析PAGEREF_Toc165779901\h2HYPERLINK\l"_Toc165779902"1.2变电站总体分析PAGEREF_Toc165779902\h3HYPERLINK\l"_Toc165779903"1.2.1建站规模PAGEREF_Toc165779903\h3HYPERLINK\l"_Toc165779904"1.2.2变电所概况PAGEREF_Toc165779904\h3HYPERLI