暫態(tài)分析—第五次作業(yè)答案和常見(jiàn)錯(cuò)誤

1、如圖所示輸電系統(tǒng)，在f點(diǎn)發(fā)牛接地短路，試?yán)L出各序網(wǎng)絡(luò)，并計(jì)算:(1) 電源的等值電勢(shì)；(2) 短路點(diǎn)的各序輸入電抗；(3) 計(jì)算變壓器I的d側(cè)的各相電壓和各相電流。T-26.3kV4W各元件的參數(shù)如下：發(fā)電機(jī):SN=I2OMVA，VN=IO.5kV 巳二 1.67 X(I)=O.9，x(2)=0.45變壓器 T-I : SN= 60MVA Vs% =10.5 kT, =10.5/115 ;變壓器 T-2 : Sn=60MVA Vs%=10.5 kT2=115/6.3 ;線路 L 每回路:I = 105km X(l)=0.41 / km X(O)= 3x(1);負(fù)荷 LD-I : S = 60M

2、VA, X(l)=l .2，XG)= 0.35 ;負(fù)荷 LD-2 : SN 40MVA, X=1 .2 X(2)=0.35。解:基準(zhǔn)功率 気=12OMVA基準(zhǔn)電壓UB =UaV各序網(wǎng)絡(luò)圖如下，圖中標(biāo)出各元件電抗標(biāo) 幺值。正序網(wǎng)：E| XG(I)167怙42.4 0.91.21Ua( i)%側(cè)等效電抗為A xgo)/xldi(i)xti(D xl(i 嚴(yán) 0.66 0.21 0.19 =1.062巳二+XLDI xGUa(】)右側(cè)等效電抗 為X2 二 xt2(i)xld2(i)=o.21 3.6 =3.81則正序網(wǎng)的等效電抗為-w=O.83 厶3.81+1.06等值電勢(shì)Ee廠亠二遠(yuǎn)炎1 =0.9

3、5qx,+ X2 3.81 +1 .06網(wǎng)：丄丄1丄X 1 2 - (X G( 2)/XlD 1(2) XT 1( 2)-X L(2)/(Xt2(2)X LD 2(2)=0.442負(fù)序零序網(wǎng)絡(luò)：X O-Xti(O) 1 XL(OrO.78假設(shè)f點(diǎn)發(fā)生了單相接地故障故障相為A相j(xVX，；)j(0.83 1.22)魏)=j(X2+X o)lfa(i)=j(0.440.78) *(-j0.46) =0.56fa(2)-二x 2 I fa(i)二0.44*( -j )0.46= J .2fa(O)jX H tad)= j0-78*(- j0.46)= -0.36TlEl-U fa(l) 1r21

4、0.56 沖.060.61XiT1(2)XG(2)/XLD1 (2) XTI (2) X L (2)A44fa(2)*( JO.46) =JO.310.67eq 0.95lfa(l) =lfa (2)=1 fa(O)=E= j 0.46則變壓器d側(cè)的電流為j30j30ITId(l)E1 ITI(l)eU-j0.61eTld(2) =，TI(2re-J3 二一朋耶。ITIda 二 ITId(l)+1 Tid(2)A0.61ej3-j0.3eT3022j30Tldb -a I Tld(l) a I Tid(2)-ja *0.61 e - ja *0.3 e-j 302ITIdC =alTid(D

5、a ITId(2)=-ja*0.61 ej 302-j30-ja 0.3e變壓器Tly側(cè)的電壓為1UM)=%j(Xti 八)56 0 461 t4804U 葉汨爲(wèi) j (XgX L(2) Tl =.2 0.4*0.3=0.08則變壓器d側(cè)的電壓為U Tld(l)=IJ Tly (l)A=0.804eU AeO6eT1d(2)b k U T1y(2)u uTldaTld(l) *,zHd(2)j 30c-j300 804e 0 08eUTIdAa2UTid(i) -al)Tid(2)=a2O.8O4ej30-aO.O8e*j30UTIdC=all Tld(l) aJ Tld=aO.8O4d30

6、-a20.08eA3見(jiàn)錯(cuò)誤：1等值電壓不會(huì)算2Y計(jì)算了零序Whe n you are OICI and grey and full Of sleep,And no ddi ng by the fire, take dow n this book,And SlOWly read, and dream Of the SOft lOOkYOUr eyes had Once, and Of their ShadOWS deep;HOW many lOVed your mome nts Of glad grace,Anel lOVeCI your beauty With lOVe false Or tr

7、ue,BUt One man lOVeCI the Pilgrim SOUI in you,AnCI lOVeel the SOrrOWS Of your Cha nging face;AnCI bending dow n beside the glow ing bars,MUrmllrj a little sadly, how lOVe fledAnd PaCeCI UPon the mountains OverheadAnd hid his face amid a CrOWCI Of stars.The furthest CliSta nee in the WOrlCIIS not bet

8、wee n life and deathBUt Whe n I Sta nd in front Of youYet you ClOrrt know thatI lOVe you.The furthest dista nee in the WOrldIS not Whe n I Sta nd in front Of youYet you CarYt See my lOVeBUt Whe n Un doubtedly knowing the lOVe from bothYet CannOt be together.The furthest CliSta nee in the WOrlcIIS not being apart While being in lOVeBUt Whe n I Pla inly cannot resist the year ningYet Prete nding you have n ever bee n in my heart.The furthest dista nee in the WOrldIS not Strllggli ng ag