变压器绕组中的短路电流峰值的确定

(,071003):,,,,:DeterminationofPeakValueofShort-CircuitCurrentinTransformerWindingsWangZhangqiandShiChuanliNorthChinaElectricPowerUniversity,Baoding071003Abstract:Therulesofshort-circuitcurrentvarianceunderthree-phaseshort-circuitconditionatLVsideoftransformerareexpoundedinthispaper.Itisprovedthatshort-circuitcurrenthasamaximumvaluewhilepowervoltagepasseszero.Anewnumericalmethodofdeterminingthemaximumvalueofshort-circuitisgiven.Keywords:Transformer,Winding,Short-circuitcurrent,Peak-value,Calculation1,,,,,,,2,,,,[1],,,,1X=LRUm/2,,[1],135519985TRANSFORMERVol.35MayNo.51998©1995-2004TsinghuaTongfangOpticalDiscCo.,Ltd.Allrightsreserved.1:u=Umsin(t+)(1),i1:i1=2I0sin(t+-)(2)I0=Um2Z=Um2(L)2+R2(3),I0,;=tg-1(X/R)=tg-1(L/R),,,,,:ik=i1+i2=2I0[sin(t+-)-sin(-)exp(-RXt)](4)[2],LmR,=/2(4):ik=i1+i2=2I0[-cos(t+)+cos()exp(-RXt)](5)-=-/2,(4)222,,,[3],,,,,,(4)f(,t)=2[sin(t+-)-sin(-)exp(-RXt)](6)(4)ik,(6)f(,t),f(,t)(m,tm)():5f(,t)5=mt=tm=05f(,t)5t=mt=tm=0(7)cos(tm+m-)-cos(m-)exp(-RXtm)=0(8a)cos(tm+m-)+RXsin(m-)exp(-RXtm)=0(8b)(8a)(8b):sin(m-)RXexp(-RXtm)+cos(m-)exp(-RXtm)=0sin(m-)RX+cos(m-)=0tg=X/R:sinm=0(9)(9),,(9)m=0(8a)(8b):cos(tm-)-cos()exp(-RXtm)=0(10)(10)m=0,(8a)(8b),,,R/Xm=0,tm=/,[3],tm=32+6235©1995-2004TsinghuaTongfangOpticalDiscCo.,Ltd.Allrightsreserved.,,tm(10),,(10),,(8a)(8b):cos(tm+-)-cos(-)exp(-RXtm)=0(11)3,:(1)R/X,tenddt,m=0,I0=1,imax=0(2)t+=dt,(4)ik=2I0[sin(t+-)-sin(-)exp(-RXt)](3)ikimax,imax=ik,tmax=tttend(4);,(2)(4),,[3]:ikm=2KI0=2I0[1+exp(-RX)][3],(4)(5),-=-/2,X/R,[3]IEC76.576(2K)X/R(4)(5)[3]IEC76.51.01.512411.476671.5091.512.01.756111.716261.7461.763.01.949601.920581.9381.954.02.089352.068462.0802.095.02.192392.176912.1842.196.02.270852.258992.2632.278.02.381782.374232.3762.3810.02.456172.450862.4522.4614.02.549372.546482.5502.55:X/R=14.0,[3]IEC76.5X/R14.0,(4),(5)[3]IEC76.5,(4),IEC76.5,IEC76.5,4a.,,b.,c.,IEC76.51..,.:,1983.2..:,1986.3..,1996,33(11):1518.725:©1995-2004TsinghuaTongfangOpticalDiscCo.,Ltd.Allrightsreserved.