电力系统短路故障分析的MATLAB辅助程序设计-短路计算程序

电力系统短路故障分析的MATLAB辅助程序设计-短路计算程序电力系统短路故障分析的MATLAB辅助程序设计-短路计算程序电力系统短路故障分析的MATLAB辅助程序设计-短路计算程序xxx公司电力系统短路故障分析的MATLAB辅助程序设计-短路计算程序文件编号：文件日期：修订次数：第1.0次更改批准审核制定方案设计，管理制度电力系统短路故障分析的MATLAB辅助程序设计电力系统短路故障可分为三相对称短路故障(three-phasebalancedfaults)和不对称短路故障(unbalancedfaults)。不对称短路故障又分为单相接地短路故障(singleline-to-groundfault)、两相短路故障(line-to-linefault)以及两相接地短路故障(doubleline-to-groundfault)。根据故障分析结果可以对继电保护装置、自动装置进行整定计算，我们可以建立算法来形成节点阻抗矩阵,利用节点阻抗矩阵来计算短路故障情况下的节点电压和线路电流。一、三相对称短路故障进行三相短路计算需要两个程序：zbuild/zbuildpi和symfault程序，zbuild、zbuildpi用来在MATLAB中形成节点阻抗矩阵，symfault用来计算三相对称故障。Zbus=zbuild(zdata)这里的参数zdata是一个(e×4)阶矩阵，e是拓扑图的总支路数目。第一列和第二列为元素两端的节点编号，第三列和第四列分别是线路的电阻、电抗的标幺值。连接在0节点和发电机节点之间的发电机阻抗可能是次暂态电抗、暂态电抗或同步电抗，而且这个矩阵中还包含并联电抗器和负荷阻抗。Zbus=zbuildpi(linedata,gendata,yload)这个函数与潮流计算程序是相容的，第一个参数linedata与潮流计算程序中的文件是一致的。第一列和第二列为节点编号；第三列到第五列分别是线路的电阻、电抗以及1/2线路电纳值，这三项都为在统一基准容量下的标幺值；最后一列是变压器分接头位置，对线路来说，必须输入1；线路无输入顺序。发电机参数不包含在Linedata参数中，而是包含在第二个参数gendata中，gendata是一个g×4阶矩阵,g是发电机总数。第一列和第二列为0节点、发电机节点编号，第三列和第四列为发电机的暂态电阻和暂态电抗。最后一个参数yload是可选择的，这个矩阵有两列，第一列为节点编号，第二列为复数导纳值，yload可以由潮流程序lfguss，lfnewton或者decouple自动生成。Zbuild和zbuildpi两个函数可以通过建立算法求出节点阻抗矩阵。首先添加所有与参考节点相连的树支，然后添加其余的树支，最后添加共轭连支。程序symfault(zdata,Zbus,V)用来计算三相对称故障，程序要求输入zdata和Zbus两个矩阵，第三个参数V是可选的。如果V不存在，程序将默认故障前所有的节点电压标幺值为，如果变量V存在，那么V包括节点编号和复数电压值。电压向量V也可以由潮流计算程序自动生成。当symfault程序运行时，用户要输入故障节点编号和故障阻抗，运行可得到总的故障电流，节点电压幅值以及故障情况下的线路电流。在三相短路计算中，zbuild和symfault程序，zbuildpi和symfault程序都可以进行计算，下面是三相短路计算使用的程序代码：（1）程序代码：function[Zbus]=zbuild(linedata)nl=linedata(:,1);nr=linedata(:,2);R=linedata(:,3);X=linedata(:,4);nbr=length(linedata(:,1));nbus=max(max(nl),max(nr));fork=1:nbrifR(k)==inf|X(k)==infR(k)=9;X(k)=9;%无穷else,endendZB=R+j*X;Zbus=zeros(nbus,nbus);tree=0;%从参考总线0上添加一个分支forI=1:nbrntree(I)=1;ifnl(I)==0|nr(I)==0ifnl(I)==0n=nr(I);elseifnr(I)==0n=nl(I);endifabs(Zbus(n,n))==0Zbus(n,n)=ZB(I);tree=tree+1;%%newelseZbus(n,n)=Zbus(n,n)*ZB(I)/(Zbus(n,n)+ZB(I));endntree(I)=2;else,endend%添加一个新总线分支到现有总线上whiletree<nbusforn=1:nbusnadd=1;ifabs(Zbus(n,n))==0forI=1:nbrifnadd==1;ifnl(I)==n|nr(I)==nifnl(I)==nk=nr(I);elseifnr(I)==nk=nl(I);endifabs(Zbus(k,k))~=0form=1:nbusifm~=nZbus(m,n)=Zbus(m,k);Zbus(n,m)=Zbus(m,k);else,endendZbus(n,n)=Zbus(k,k)+ZB(I);tree=tree+1;nadd=2;ntree(I)=2;else,endelse,endelse,endendelse,endendend%增加两个原有总线间的支路阻抗forn=1:nbusforI=1:nbrifntree(I)==1ifnl(I)==n|nr(I)==nifnl(I)==nk=nr(I);elseifnr(I)==nk=nl(I);endDM=Zbus(n,n)+Zbus(k,k)+ZB(I)-2*Zbus(n,k);forjj=1:nbusAP=Zbus(jj,n)-Zbus(jj,k);forkk=1:nbusAT=Zbus(n,kk)-Zbus(k,kk);DELZ(jj,kk)=AP*AT/DM;endendZbus=Zbus-DELZ;ntree(I)=2;else,endelse,endendend（2）程序代码：%Thisprogramformsthecomplexbusimpedancematrixbythemethod%ofbuildingalgorithm.Buszeroistakenasreference.%Thisprogramiscompatiblewithpowerflowdata.function[Zbus,linedata]=zbuildpi(linedata,gendata,yload)ng=length(gendata(:,1));nlg=gendata(:,1);nrg=gendata(:,2);zg=gendata(:,2)+j*gendata(:,3);nl=linedata(:,1);nr=linedata(:,2);R=linedata(:,3);X=linedata(:,4);nbr=length(linedata(:,1));nbus=max(max(nl),max(nr));nc=length(linedata(1,:));fork=1:nbrifR(k)==inf|X(k)==infR(k)=;X(k)=;else,endendifnc>4BC=linedata(:,5);forn=1:nbusyc(n)=0;nlc(n)=0;nrc(n)=n;fork=1:nbrifnl(k)==n|nr(k)==nyc(n)=yc(n)+j*BC(k);else,endendendelseifnc==4yc=zeros(1,nbr);endnlc=nlc';nrc=nrc';yc=yc.';ZB=R+j*X;ifexist('yload')==1yload=yload.';yc=yc+yload;else,endm=0;forn=1:nbusifabs(yc(n))~=0m=m+1;nlcc(m)=nlc(n);nrcc(m)=nrc(n);zc(m)=1/yc(n);else,endendnlcc=nlcc';nrcc=nrcc';zc=zc.';nl=[nlg;nlcc;nl];nr=[nrg;nrcc;nr];ZB=[zg;zc;ZB];linedata=[nlnrreal(ZB)imag(ZB)];nbr=length(nl);Zbus=zeros(nbus,nbus);tree=0;%%从参考总线0上添加一个分支forI=1:nbrntree(I)=1;ifnl(I)==0|nr(I)==0ifnl(I)==0n=nr(I);elseifnr(I)==0n=nl(I);endifabs(Zbus(n,n))==0Zbus(n,n)=ZB(I);tree=tree+1;elseZbus(n,n)=Zbus(n,n)*ZB(I)/(Zbus(n,n)+ZB(I));endntree(I)=2;else,endend%%添加一个新总线分支到现有总线上whiletree<nbusforn=1:nbusnadd=1;ifabs(Zbus(n,n))==0forI=1:nbrifnadd==1ifnl(I)==n|nr(I)==nifnl(I)==nk=nr(I);elseifnr(I)==nk=nl(I);endifabs(Zbus(k,k))~=0form=1:nbusifm~=nZbus(m,n)=Zbus(m,k);Zbus(n,m)=Zbus(m,k);else,endendZbus(n,n)=Zbus(k,k)+ZB(I);tree=tree+1;nadd=2;ntree(I)=2;else,endelse,endelse,endendelse,endendend%增加两个原有总线间的支路阻抗forn=1:nbusforI=1:nbrifntree(I)==1ifnl(I)==n|nr(I)==nifnl(I)==nk=nr(I);elseifnr(I)==nk=nl(I);endDM=Zbus(n,n)+Zbus(k,k)+ZB(I)-2*Zbus(n,k);forjj=1:nbusAP=Zbus(jj,n)-Zbus(jj,k);forkk=1:nbusAT=Zbus(n,kk)-Zbus(k,kk);DELZ(jj,kk)=AP*AT/DM;endendZbus=Zbus-DELZ;ntree(I)=2;else,endelse,endendend（3）程序代码：%此程序用来计算电网的三相对称故障%计算前需要用户生成节点阻抗矩阵%节点阻抗矩阵可由函数Zbus=zbuild(zdata)生成%此程序需要用户按提示输入短路节点编号和过度电阻Zf%向量V是可选参数，包含节点编号和复数电压%V可由潮流程序lfgauss,lfnewton,decouple自动生成.%如果V不存在，程序将默认故障前所有的节点电压标幺值为%程序可得到总的故障电流,节点电压幅值及输电线路的电流functionsymfaul(zdata,Zbus,V)nl=zdata(:,1);nr=zdata(:,2);R=zdata(:,3);X=zdata(:,4);nc=length(zdata(1,:));ifnc>4BC=zdata(:,5);elseifnc==4,BC=zeros(length(zdata(:,1)),1);endZB=R+j*X;nbr=length(zdata(:,1));nbus=max(max(nl),max(nr));ifexist('V')==1iflength(V)==nbusV0=V;else,endelse,V0=ones(nbus,1)+j*zeros(nbus,1);endfprintf('\Three-phasebalancedfaultanalysis\n')ff=999;whileff>0nf=input('EnterFaultedBusNo.->');rtn=isempty(nf);ifrtn==1;nf=-1;endwhilenf<=0|nf>nbusfprintf('FaultedbusNo.mustbebetween1&%g\n',nbus)nf=input('EnterFaultedBusNo.->');rtn=isempty(nf);ifrtn==1;nf=-1;endendrtz=1;whilertz==1fprintf('\nEnterFaultImpedanceZf=R+j*Xin')Zf=input('complexform(forboltedfaultenter0).Zf=');rtz=isempty(Zf);endfprintf('\n')fprintf('Balancedthree-phasefaultatbusNo.%g\n',nf)If=V0(nf)/(Zf+Zbus(nf,nf));Ifm=abs(If);Ifmang=angle(If)*180/pi;fprintf('Totalfaultcurrent=%perunit\n\n',Ifm)%fprintf('.\n\n',Ifm)fprintf('BusVoltagesduringfaultinperunit\n\n')fprintf('BusVoltageAngle\n')fprintf('No.Magnitudedegrees\n')forn=1:nbusifn==nfVf(nf)=V0(nf)*Zf/(Zf+Zbus(nf,nf));Vfm=abs(Vf(nf));angv=angle(Vf(nf))*180/pi;else,Vf(n)=V0(n)-V0(n)*Zbus(n,nf)/(Zf+Zbus(nf,nf));Vfm=abs(Vf(n));angv=angle(Vf(n))*180/pi;endfprintf('%4g',n),fprintf('%',Vfm),fprintf('%\n',angv)endfprintf('\n')fprintf('LinecurrentsforfaultatbusNo.%g\n\n',nf)fprintf('FromToCurrentAngle\n')fprintf('BusBusMagnitudedegrees\n')forn=1:nbusforI=1:nbrifnl(I)==n|nr(I)==nifnl(I)==nk=nr(I);elseifnr(I)==nk=nl(I);endifk==0Ink=(V0(n)-Vf(n))/ZB(I);Inkm=abs(Ink);th=angle(Ink);ifreal(Ink)>0fprintf('G'),fprintf('%7g',n),fprintf('%',Inkm)fprintf('%\n',th*180/pi)elseifreal(Ink)==0&imag(Ink)<0fprintf('G'),fprintf('%7g',n),fprintf('%',Inkm)fprintf('%\n',th*180/pi)else,endIgn=Ink;elseifk~=0Ink=(Vf(n)-Vf(k))/ZB(I)+BC(I)*Vf(n);Inkm=abs(Ink);th=angle(Ink);ifreal(Ink)>0fprintf('%7g',n),fprintf('%10g',k),fprintf('%',Inkm),fprintf('%\n',th*180/pi)elseifreal(Ink)==0&imag(Ink)<0fprintf('%7g',n),fprintf('%10g',k),fprintf('%',Inkm),fprintf('%\n',th*180/pi)else,endelse,endelse,endendifn==nffprintf('%7g',n),fprintf('F'),fprintf('%',Ifm)fprintf('%\n',Ifmang)else,endendresp=0;whilestrcmp(resp,'n')~=1&strcmp(resp,'N')~=1&strcmp(resp,'y')~=1&strcmp(resp,'Y')~=1resp=input('AnotherfaultlocationEnter''y''or''n''withinsinglequote->');ifstrcmp(resp,'n')~=1&strcmp(resp,'N')~=1&strcmp(resp,'y')~=1&strcmp(resp,'Y')~=1fprintf('\nIncorrectreply,tryagain\n\n'),endendifresp=='y'|resp=='Y'nf=999;elseff=0;endend二、不对称短路故障不对称故障包括单相接地短路(singleline-to-groundfault)，两相短路(line-to-linefault)，和两相接地短路(doubleline-to-groundfault)。这里介绍三个程序来分析不对称短路故障：单相接地lgfault(zdata0,zbus0,zdata1,zbus1,zdata2,zbus2,V)两相短路llfault(zdata1,zbus1,zdata2,zbus2,V)两相接地短路dlgfault(zdata0,zbus0,zdata1,zbus1,zdata2,zbus2,V)对于lgfault和dlgfault需要输入正序、零序、负序节点阻抗矩阵Zbus1、Zbus0和Zbus2，而llfault只需输入正序和负序节点阻抗矩阵Zbus1、Zbus2，最后参数V是可以选择的。如果用户未输入V，程序则默认所有故障前的电压为。如果用户输入参数V，则需要输入节点编号以及节点电压的复数值。变量V可由潮流计算程序获得。零序网络和正序网络的节点阻抗矩阵分别通过函数Zbus0=zbuild（zdata0）和Zbus1=zbuild（zdata1）获得。参数zdata1包含正序网络阻抗，参数zdata0包含零序网络阻抗。参数zdata1、zdata2、zdata0均为e×4阶矩阵，e为元件的个数。第一列和第二列是节点编号，第三列和第四列分别是线路电阻和电抗（均为标幺值）。节点0为参考节点，发电机节点到节点0的阻抗为发电机阻抗，可以是发电机的次暂态电抗、暂态电抗或者同步电抗，而且矩阵还包括并联电容和负荷阻抗等。负序网络和正序网络有同样的拓扑结构。线路和变压器的负序阻抗等于正序阻抗，而发电机的负序阻抗不等于正序阻抗，但在大型电力系统故障分析中通常按相等来计算。零序网络的拓扑结构不同于正序网络，零序网络的构建取决于变压器的绕组连接方式，除了两侧中性点都接地的Y-Y连接的变压器，对于其他连接方式的变压器，一次侧和二次侧的零序网络都是隔离开的。在这样的连接方式的零序网络中,，用inf填写对应的电阻和电抗列。对于Y-△（中性点接地）连接的变压器，Y侧的阻抗到节点0的数据需要填写。当中性点接地阻抗为Xn时，需要填写为3Xn。在不对称故障计算时，还需要一个函数用来求节点阻抗矩阵，Zbus=zbuildpi（linedata，gendata，yload），函数与潮流计算程序是相容的。第一个参数linedata与潮流程序所需要的数据相同。第一列和第二列是节点编号；第三列到第五列分别是线路的电阻、电抗、1/2线路电纳（均为标幺值，以指定的MVA为基准功率）；最后一列为变压器分接头位置，对于线路，在这一列中必须填写1。在潮流计算程序中，发电机电抗不包含在参数linedata中，而是包含在参数gendata中。参数gendata是一个(g×4)阶矩阵，其四列分别为参考节点0、发电机节点编号、发电机电阻和电抗。最后一个参数yload是可选的，这是一个两列的矩阵，包括节点编号和负荷复数导纳值。这些数据可以从潮流计算程序lfgauss，lfnewton，decouple执行过程中自动生成。程序运行时会提示用户输入故障节点编号和故障阻抗Zf，运行结果可得到故障电流，节点电压和线路电流。不对称短路故障计算使用的程序如下：（1）程序代码：%Theprogramlgfaultisdesignedforthesingleline-to-ground%faultanalysisofapowersystemnetwork.Theprogramrequires%thepositive-,negative-andzero-sequencebusimpedancematrices,%Zbus1Zbus2,andbusimpedancesmatricesmaybedefined%bytheuser,obtainedbytheinversionofYbusoritmaybe%determinedeitherfromthefunctionZbus=zbuild(zdata)%orthefunctionZbus=zbuildpi(linedata,gendata,yload).%Theprogrampromptstheusertoenterthefaultedbusnumber%andthefaultimpedanceZf.Theprefaultbusvoltagesare%definedbythereservedVectorV.ThearrayVmaybedefinedor%itisreturnedfromthepowerflowprogramslfgauss,lfnewton,%decoupleorperturb.IfVdoesnotexisttheprefaultbusvoltages%areautomaticallysettoperunit.Theprogramobtainsthe%totalfaultcurrent,busvoltagesandlinecurrentsduringthefault.functionlgfault(zdata0,Zbus0,zdata1,Zbus1,zdata2,Zbus2,V)ifexist('zdata2')~=1zdata2=zdata1;else,endifexist('Zbus2')~=1Zbus2=Zbus1;else,endnl=zdata1(:,1);nr=zdata1(:,2);nl0=zdata0(:,1);nr0=zdata0(:,2);nbr=length(zdata1(:,1));nbus=max(max(nl),max(nr));nbr0=length(zdata0(:,1));R0=zdata0(:,3);X0=zdata0(:,4);R1=zdata1(:,3);X1=zdata1(:,4);R2=zdata1(:,3);X2=zdata1(:,4);fork=1:nbr0ifR0(k)==inf|X0(k)==infR0(k)=;X0(k)=;else,endendZB1=R1+j*X1;ZB0=R0+j*X0;ZB2=R2+j*X2;ifexist('V')==1iflength(V)==nbusV0=V;else,endelse,V0=ones(nbus,1)+j*zeros(nbus,1);endfprintf('\nLine-to-groundfaultanalysis\n')ff=999;whileff>0nf=input('EnterFaultedBusNo.->');rtn=isempty(nf);ifrtn==1;nf=-1;endwhilenf<=0|nf>nbusfprintf('FaultedbusNo.mustbebetween1&%g\n',nbus)nf=input('EnterFaultedBusNo.->');rtn=isempty(nf);ifrtn==1;nf=-1;endendrtz=1;whilertz==1fprintf('\nEnterFaultImpedanceZf=R+j*Xin')Zf=input('complexform(forboltedfaultenter0).Zf=');rtz=isempty(Zf);endfprintf('\n')fprintf('Singlelineto-groundfaultatbusNo.%g\n',nf)a=cos(2*pi/3)+j*sin(2*pi/3);sctm=[111;1a^2a;1aa^2];Ia0=V0(nf)/(Zbus1(nf,nf)+Zbus2(nf,nf)+Zbus0(nf,nf)+3*Zf);Ia1=Ia0;Ia2=Ia0;I012=[Ia0;Ia1;Ia2];Ifabc=sctm*I012;Ifabcm=abs(Ifabc);fprintf('Totalfaultcurrent=%perunit\n\n',Ifabcm(1))fprintf('BusVoltagesduringthefaultinperunit\n\n')fprintf('Bus-------VoltageMagnitude-------\n')fprintf('No.PhaseaPhasebPhasec\n')forn=1:nbusVf0(n)=0-Zbus0(n,nf)*Ia0;Vf1(n)=V0(n)-Zbus1(n,nf)*Ia1;Vf2(n)=0-Zbus2(n,nf)*Ia2;Vabc=sctm*[Vf0(n);Vf1(n);Vf2(n)];Va(n)=Vabc(1);Vb(n)=Vabc(2);Vc(n)=Vabc(3);fprintf('%5g',n)fprintf('%',abs(Va(n))),fprintf('%',abs(Vb(n)))fprintf('%\n',abs(Vc(n)))endfprintf('\n')fprintf('LinecurrentsforfaultatbusNo.%g\n\n',nf)fprintf('FromTo-----LineCurrentMagnitude----\n')fprintf('BusBusPhaseaPhasebPhasec\n')forn=1:nbusforI=1:nbrifnl(I)==n|nr(I)==nifnl(I)==nk=nr(I);elseifnr(I)==nk=nl(I);endifk~=0Ink1(n,k)=(Vf1(n)-Vf1(k))/ZB1(I);Ink2(n,k)=(Vf2(n)-Vf2(k))/ZB2(I);else,endelse,endendforI=1:nbr0ifnl0(I)==n|nr0(I)==nifnl0(I)==nk=nr0(I);elseifnr0(I)==nk=nl0(I);endifk~=0Ink0(n,k)=(Vf0(n)-Vf0(k))/ZB0(I);else,endelse,endendforI=1:nbrifnl(I)==n|nr(I)==nifnl(I)==nk=nr(I);elseifnr(I)==nk=nl(I);endifk~=0Inkabc=sctm*[Ink0(n,k);Ink1(n,k);Ink2(n,k)];Inkabcm=abs(Inkabc);th=angle(Inkabc);ifreal(Inkabc(1))>0fprintf('%7g',n),fprintf('%10g',k),fprintf('%',abs(Inkabc(1))),fprintf('%',abs(Inkabc(2)))fprintf('%\n',abs(Inkabc(3)))elseifreal(Inkabc(1))==0&imag(Inkabc(1))<0fprintf('%7g',n),fprintf('%10g',k),fprintf('%',abs(Inkabc(1))),fprintf('%',abs(Inkabc(2)))fprintf('%\n',abs(Inkabc(3)))else,endelse,endelse,endendifn==nffprintf('%7g',n),fprintf('F'),fprintf('%',Ifabcm(1)),fprintf('%',Ifabcm(2))fprintf('%\n',Ifabcm(3))else,endendresp=0;whilestrcmp(resp,'n')~=1&strcmp(resp,'N')~=1&strcmp(resp,'y')~=1&strcmp(resp,'Y')~=1resp=input('AnotherfaultlocationEnter''y''or''n''withinsinglequote->');ifstrcmp(resp,'n')~=1&strcmp(resp,'N')~=1&strcmp(resp,'y')~=1&strcmp(resp,'Y')~=1fprintf('\nIncorrectreply,tryagain\n\n'),endendifresp=='y'|resp=='Y'nf=999;elseff=0;endend（2）程序代码：%Theprogramllfaultisdesignedfortheline-to-line%faultanalysisofapowersystemnetwork.Theprogramrequires%thepositive-andnegative-sequencebusimpedancematrices,%Zbus1,andbusimpedancesmatricesmaybedefined%bytheuser,obtainedbytheinversionofYbusoritmaybe%determinedeitherfromthefunctionZbus=zbuild(zdata)%orthefunctionZbus=zbuildpi(linedata,gendata,yload).%Theprogrampromptstheusertoenterthefaultedbusnumber%andthefaultimpedanceZf.Theprefaultbusvoltagesare%definedbythereservedVectorV.ThearrayVmaybedefinedor%itisreturnedfromthepowerflowprogramslfgauss,lfnewton,%decoupleorperturb.IfVdoesnotexisttheprefaultbusvoltages%areautomaticallysettoperunit.Theprogramobtainsthe%totalfaultcurrent,busvoltagesandlinecurrentsduringthefault.functionllfault(zdata1,Zbus1,zdata2,Zbus2,V)ifexist('zdata2')~=1zdata2=zdata1;else,endifexist('Zbus2')~=1Zbus2=Zbus1;else,endnl=zdata1(:,1);nr=zdata1(:,2);R1=zdata1(:,3);X1=zdata1(:,4);R2=zdata2(:,3);X2=zdata2(:,4);ZB1=R1+j*X1;ZB2=R2+j*X2;nbr=length(zdata1(:,1));nbus=max(max(nl),max(nr));ifexist('V')==1iflength(V)==nbusV0=V;else,endelse,V0=ones(nbus,1)+j*zeros(nbus,1);endfprintf('\nLine-to-linefaultanalysis\n')ff=999;whileff>0nf=input('EnterFaultedBusNo.->');rtn=isempty(nf);ifrtn==1;nf=-1;endwhilenf<=0|nf>nbusfprintf('FaultedbusNo.mustbebetween1&%g\n',nbus)nf=input('EnterFaultedBusNo.->');rtn=isempty(nf);ifrtn==1;nf=-1;endendrtz=1;whilertz==1fprintf('\nEnterFaultImpedanceZf=R+j*Xin')Zf=input('complexform(forboltedfaultenter0).Zf=');rtz=isempty(Zf);endfprintf('\n')fprintf('Line-to-linefaultatbusNo.%g\n',nf)a=cos(2*pi/3)+j*sin(2*pi/3);sctm=[111;1a^2a;1aa^2];Ia0=0;Ia1=V0(nf)/(Zbus1(nf,nf)+Zbus2(nf,nf)+Zf);Ia2=-Ia1;I012=[Ia0;Ia1;Ia2];Ifabc=sctm*I012;Ifabcm=abs(Ifabc);fprintf('Totalfaultcurrent=%perunit\n\n',Ifabcm(2))fprintf('BusVoltagesduringthefaultinperunit\n\n')fprintf('Bus-------VoltageMagnitude-------\n')fprintf('No.PhaseaPhasebPhasec\n')forn=1:nbusVf0(n)=0;Vf1(n)=V0(n)-Zbus1(n,nf)*Ia1;Vf2(n)=0-Zbus2(n,nf)*Ia2;Vabc=sctm*[Vf0(n);Vf1(n);Vf2(n)];Va(n)=Vabc(1);Vb(n)=Vabc(2);Vc(n)=Vabc(3);fprintf('%5g',n)fprintf('%',abs(Va(n))),fprintf('%',abs(Vb(n)))fprintf('%\n',abs(Vc(n)))endfprintf('\n')fprintf('LinecurrentsforfaultatbusNo.%g\n\n',nf)fprintf('FromTo-----LineCurrentMagnitude----\n')fprintf('BusBusPhaseaPhasebPhasec\n')forn=1:nbusforI=1:nbrifnl(I)==n|nr(I)==nifnl(I)==nk=nr(I);elseifnr(I)==nk=nl(I);endifk~=0Ink0(n,k)=0;Ink1(n,k)=(Vf1(n)-Vf1(k))/ZB1(I);Ink2(n,k)=(Vf2(n)-Vf2(k))/ZB2(I);Inkabc=sctm*[Ink0(n,k);Ink1(n,k);Ink2(n,k)];Inkabcm=abs(Inkabc);th=angle(Inkabc);ifreal(Inkabc(2))<0fprintf('%7g',n),fprintf('%10g',k),fprintf('%',abs(Inkabc(1))),fprintf('%',abs(Inkabc(2)))fprintf('%\n',abs(Inkabc(3)))elseifreal(Inkabc(2))==0&imag(Inkabc(2))>0fprintf('%7g',n),fprintf('%10g',k),fprintf('%',abs(Inkabc(1))),fprintf('%',abs(Inkabc(2)))fprintf('%\n',abs(Inkabc(3)))else,endelse,endelse,endendifn==nffprintf('%7g',n),fprintf('F'),fprintf('%',Ifabcm(1)),fprintf('%',Ifabcm(2))fprintf('%\n',Ifabcm(3))else,endendresp=0;whilestrcmp(resp,'n')~=1&strcmp(resp,'N')~=1&strcmp(resp,'y')~=1&strcmp(resp,'Y')~=1resp=input('AnotherfaultlocationEnter''y''or''n''withinsinglequote->');ifstrcmp(resp,'n')~=1&strcmp(resp,'N')~=1&strcmp(resp,'y')~=1&strcmp(resp,'Y')~=1fprintf('\nIncorrectreply,tryagain\n\n'),endendifresp=='y'|resp=='Y'nf=999;elseff=0;endend（3）程序代码：%Theprogramdlgfaultisdesignedforthedoubleline-to-ground%faultanalysisofapowersystemnetwork.Theprogramrequires%thepositive-,negative-orzero-sequencebusimpedancematrices,%Zbus1Zbus2,andZbus0.Thebusimpedancesmatricesmaybedefined%bytheuser,obtainedbytheinversionofYbusoritmaybe%determinedeitherfromthefunctionZbus=zbuild(zdata)%orthefunctionZbus=zbuildpi(linedata,gendata,yload).%Theprogrampromptstheusertoenterthefaultedbusnumber%andthefaultimpedanceZf.Theprefaultbusvoltagesare%definedbythereservedVectorV.ThearrayVmaybedefinedor%itisreturnedfromthepowerflowprogramslfgauss,lfnewton,%decoupleorperturb.IfVdoesnotexisttheprefaultbusvoltages%areautomaticallysettoperunit.Theprogramobtainsthe%totalfaultcurrent,busvoltagesandlinecurrentsduringthefault.functiondlgfault(zdata0,Zbus0,zdata1,Zbus1,zdata2,Zbus2,V)ifexist('zdata2')~=1zdata2=zdata1;else,endifexist('Zbus2')~=1Zbus2=Zbus1;else,endnl=zdata1(:,1);nr=zdata1(:,2);nl0=zdata0(:,1);nr0=zdata0(:,2);nbr=length(zdata1(:,1));nbus=max(max(nl),max(nr));nbr0=length(zdata0(:,1));R0=zdata0(:,3);X0=zdata0(:,4);R1=zdata1(:,3);X1=zdata1(:,4);R2=zdata2(:,3);X2=zdata2(:,4);fork=1:nbr0ifR0(k)==inf|X0(k)==infR0(k)=;X0(k)=9;else,endendZB1=R1+j*X1;ZB0=R0+j*X0;ZB2=R2+j*X2;ifexist('V')==1iflength(V)==nbusV0=V;else,endelse,V0=ones(nbus,1)+j*zeros(nbus,1);endfprintf('\nDoubleline-to-groundfaultanalysis\n')ff=999;whileff>0nf=input('EnterFaultedBusNo.->');rtn=isempty(nf);ifrtn==1;nf=-1;endwhilenf<=0|nf>nbusfprintf('FaultedbusNo.mustbebetween1&%g\n',nbus)nf=input('EnterFaultedBusNo.->');rtn=isempty(nf);ifrtn==1;nf=-1;endendrtz=1;whilertz==1fprintf('\nEnterFaultImpedanceZf=R+j*Xin')Zf=input('complexform(forboltedfaultenter0).Zf=');rtz=isempty(Zf);endfprintf('\n')fprintf('Doubleline-to-groundfaultatbusNo.%g\n',nf)a=cos(2*pi/3)+j*sin(2*pi/3);sctm=[111;1a^2a;1aa^2];Z11=Zbus2(nf,nf)*(Zbus0(nf,nf)+3*Zf)/(Zbus2(nf,nf)+Zbus0(nf,nf)+3*Zf);Ia1=V0(nf)/(Zbus1(nf,nf)+Z11);Ia2=-(V0(nf)-Zbus1(nf,nf)*Ia1)/Zbus2(nf,nf);Ia0=-(V0(nf)-Zbus1(nf,nf)*Ia1)/(Zbus0(nf,nf)+3*Zf);I012=[Ia0;Ia1;Ia2];Ifabc=sctm*I012;Ifabcm=abs(Ifabc);Ift=Ifabc(2)+Ifabc(3);Iftm=abs(Ift);fprintf('Totalfaultcurrent=%perunit\n\n',Iftm)fprintf('BusVoltagesduringthefaultinperunit\n\n')fprintf('Bus-------VoltageMagnitude-------\n')fprintf('No.PhaseaPhasebPhasec\n')forn=1:nbusVf0(n)=0-Zbus0(n,nf)*Ia0;Vf1(n)=V0(n)-Zbus1(n,nf)*Ia1;Vf2(n)=0-Zbus2(n,nf)*Ia2;Vabc=sctm*[Vf0(n);Vf1(n);Vf2(n)];Va(n)=Vabc(1);Vb(n)=Vabc(2);Vc(n)=Vabc(3);fprintf('%5g',n)fprintf('%',abs(Va(n))),fprintf('%',abs(Vb(n)))fprintf('%\n',abs(Vc(n)))endfprintf('\n')fprintf('LinecurrentsforfaultatbusNo.%g\n\n',nf)fprintf('FromTo-----LineCurrentMagnitude----\n')fprintf('BusBusPhaseaPhasebPhasec\n')forn=1:nbusforI=1:nbrifnl(I)==n|nr(I)==nifnl(I)==nk=nr(I);elseifnr(I)==nk=nl(I);endifk~=0Ink1(n,k)=(Vf1(n)-Vf1(k))/ZB1(I);Ink2(n,k)=(Vf2(n)-Vf2(k))/ZB2(I);else,endelse,endendforI=1:nbr0ifnl0(I)==n|nr0(I)==nifnl0(I)==nk=nr0(I);elseifnr0(I)==nk=nl0(I);endifk~=0Ink0(n,k)=(Vf0(n)-Vf0(k))/ZB0(I);else,endelse,endendforI=1:nbrifnl(I)==n|nr(I)==nifnl(I)==nk=nr(I);elseifnr(I)==nk=nl(I);endifk~=0Inkabc=sctm*[Ink0(n,k);Ink1(n,k);Ink2(n,k)];Inkabcm=abs(Inkabc);th=angle(Inkabc);ifreal(Inkabc(2))<0fprintf('%7g',n),fprintf('%10g',k),fprintf('%',abs(Inkabc(1))),fprintf('%',abs(Inkabc(2)))fprintf('%\n',abs(Inkabc(3)))elseifreal(Inkabc(2))==0&imag(Inkabc(2))>0fprintf('%7g',n),fprintf('%10g',k),fprintf('%',abs(Inkabc(1))),fprintf('%',abs(Inkabc(2)))fprintf('%\n',abs(Inkabc(3)))else,endelse,endelse,endendifn==nffprintf('%7g',n),fprintf('F'),fprintf('%',Ifabcm(1)),fprintf('%',Ifabcm(2))fprintf('%\n',Ifabcm(3))else,endendresp=0;whilestrcmp(resp,'n')~=1&strcmp(resp,'N')~=1&strcmp(resp,'y')~=1&strcmp(resp,'Y')~=1resp=input('AnotherfaultlocationEnter''y''or''n''withinsinglequote->');ifstrcmp(resp,'n')~=1&strcmp(resp,'N')~=1&strcmp(resp,'y')~=1&strcmp(resp,'Y')~=1fprintf('\nIncorrectreply,tryagain\n\n'),endendifresp=='y'|resp=='Y'nf=999;elseff=0;endend三、短路故障计算实例一个简单的11节点电力系统网络如图1所示，发电机的正序、零序电抗以及中性点接地电抗见表1。变压器连接方式如图1所示,节点11和节点7之间的变压器为△-Y连接，接地电抗为。线路和变压器正序、零序电抗标幺值见表2，基准功率为100MVA。忽略电阻、并联电抗和负荷，并假设所有的负序电抗等于正序电抗。试用函数zbuild求正序和零序网络的节点阻抗矩阵,假定故障前所有的节点电压都为，用lgfault，llfault,dlgfault和symfault计算下列故障情况下的故障电流、节点电压和线路电流。(a)母线2处发生金属性单相接地故障;(b)母线4处发生金属性两相短路故障(c)母线6处发生金属性两相接地短路故障;(d)母线8处发生三相对称故障;图111节点电力系统连接图图211节点电力系统Simulink仿真图表1发电机次暂态电抗发电机次暂态电抗节点编号X1X0Xn11011表2线路和变压器参数线路和变压器参数节点编号节点编号X1X0122325263436464941057687871189在MATLAB的命令窗口输入正序、零序阻抗数据以及求解指令：zdata1=[010100111223252634