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ID:52454367
大小:1.71 MB
页数:48页
时间:2020-03-27
《电力系统分析英文课件PowerFlowAnalysis.pdf》由会员上传分享,免费在线阅读,更多相关内容在行业资料-天天文库。
1、ECE421/599ElectricEnergySystems6–PowerFlowAnalysisInstructor:KaiSunFall20141Introduction•Powerflow(loadflow)analysis–Steady-stateanalysisofaninterconnectedpowersystem–TosolvethepowerflowequationsforV(i.e.
2、V
3、andδ)andS(i.e.iiiiPandQ)ii–Basisofpowersystemanalysisanddesign•Assumptionsforapowe
4、rsystemtobestudied–Balancedconditions–Representedbyasingle-phasenetwork–Modeledbynodes(buses)andbranches–Allimpedances/admittancesareinperunitonacommonMVAbase(typically100MVA)2E1EBusAdmittanceMatrix2•Branchadmittancey=11=ijz10=z=zr+jxz=20ijijijI1201•ApplyKCLtonodes(buses)1-4V1IyVyVVyVV=+(
5、)()−+−110112121313z=z23=IyVyVVyVV=+()()−+−132202122123230()()()=yVVyVVyVV−+−+−2332133134340()=yVV344−3z34=Ii:currentinjectedbyanequivalentcurrentsourceIyyyVy=++()−−VyV11012131122133∆I=−(EVy)=Ey+−(0VyI)=+−(0Vy)I=−+++yV()yyyVyV−0111101101101110212120122322330=−−yVyV()+++yyyVyV−1312321323343
6、3440=−+yVyV343344nnIVi=i∑∑yij−yVijjj=0,1,ji≠=jji≠Yyyy11=++101213YYy12=21=−12YY14=41=0Yyyy=++YYy==−22201223133113YY==04224Yyyy33=++132334YYy23=32=−23Yy=4434YYy==−3443343IYVYVYVYV1=+++111122133144IV11YYYY1112...1in...1IVYY...YY...IYVYVYVYV=+++22212222in2211222233244:::
7、:::=IYVYVYVYV=+++IVYYYY......3311322333344iii12iiiin::::::IYVYVYVYV=+++4411422433444IVYYYY......nnn12ninnnnnnIi=−=Vi∑∑∑yijyVijjYVijjI=YVbusbusbusj=0,ji≠=jji1,≠j=1•I:currentsinjectedbyexternalcurrentsourcesbus•V:busvoltagesrelativetoareference(notinclu
8、ded),usuallythegroundbus•Y:busadmittancematrix(symmetricandsparse)bus–Diagonalelements:calledself-admittancesordrivingpointadmittancesnYyii=∑ijj=0,ji≠–Off-diagonalelements:calledmutualadmittancesortransferadmittancesYYyij=ji=−ijji≠•Z=Y-1:busimpedancematrixbusbus-1V=YI=ZIbusbusbusbusbus4
9、−jjj8.502.505.000E1E2jjj2.50−8.755.000Y=busz=z=jjjj5.005.00−22.5012.501020z12=00jj12.50−12.50Howmanynon-zeroelementsforasystemwithNbuses(notincludingtheground)andMbranches?z13=z23=2M+Njjjj0.500.400.450.45z34=jjjj0.400.480.440.44ZY=−1=busbusjjjj0.45
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