fprintf('%7g', n), fprintf('g', k),
fprintf(' .4f', abs(Inkabc(1))),fprintf(' .4f', abs(Inkabc(2))) fprintf(' .4f\\n', abs(Inkabc(3)))
elseif real(Inkabc(1)) ==0 & imag(Inkabc(1)) < 0 fprintf('%7g', n), fprintf('g', k),
fprintf(' .4f', abs(Inkabc(1))),fprintf(' .4f', abs(Inkabc(2))) fprintf(' .4f\\n', abs(Inkabc(3))) else, end else, end else, end end if n==nf
fprintf('%7g',n), fprintf(' F'),
fprintf(' .4f', Ifabcm(1)),fprintf(' .4f', Ifabcm(2)) fprintf(' .4f\\n', Ifabcm(3)) else, end end resp=0;
while strcmp(resp, 'n')~=1 & strcmp(resp, 'N')~=1 & strcmp(resp, 'y')~=1 & strcmp(resp, 'Y')~=1
resp = input('Another fault location? Enter ''y'' or ''n'' within single quote -> ');
if strcmp(resp, 'n')~=1 & strcmp(resp, 'N')~=1 & strcmp(resp, 'y')~=1 & strcmp(resp, 'Y')~=1
fprintf('\\n Incorrect reply, try again \\n\\n'), end end
if resp == 'y' | resp == 'Y' nf = 999; else ff = 0; end end
（2）llfault.m程序代码：
% The program llfault is designed for the line-to-line
% fault analysis of a power system network. The program requires % the positive- and negative-sequence bus impedance matrices, % Zbus1, and Zbus2.The bus impedances matrices may be defined % by the user, obtained by the inversion of Ybus or it may be % determined either from the function Zbus = zbuild(zdata) % or the function Zbus = zbuildpi(linedata, gendata, yload). % The program prompts the user to enter the faulted bus number % and the fault impedance Zf. The prefault bus voltages are % defined by the reserved Vector V. The array V may be defined or
% it is returned from the power flow programs lfgauss, lfnewton, % decouple or perturb. If V does not exist the prefault bus voltages % are automatically set to 1.0 per unit. The program obtains the % total fault current, bus voltages and line currents during the fault.
function llfault(zdata1, Zbus1, zdata2, Zbus2, V) if exist('zdata2') ~= 1 zdata2=zdata1; else, end
if exist('Zbus2') ~= 1 Zbus2=Zbus1; else, end
nl = 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)); if exist('V') == 1 if length(V) == nbus V0 = V; else, end
else, V0 = ones(nbus, 1) + j*zeros(nbus, 1); end
fprintf('\\nLine-to-line fault analysis \\n') ff = 999; while ff > 0
nf = input('Enter Faulted Bus No. -> '); rtn=isempty(nf); if rtn==1; nf=-1; end while nf <= 0 | nf > nbus
fprintf('Faulted bus No. must be between 1 & %g \\n', nbus) nf = input('Enter Faulted Bus No. -> '); rtn=isempty(nf); if rtn==1; nf=-1; end end rtz=1; while rtz==1
fprintf('\\nEnter Fault Impedance Zf = R + j*X in ')
Zf = input('complex form (for bolted fault enter 0). Zf = '); rtz=isempty(Zf); end
fprintf(' \\n')
fprintf('Line-to-line fault at bus No. %g\\n', nf)
a =cos(2*pi/3)+j*sin(2*pi/3);
sctm = [1 1 1; 1 a^2 a; 1 a a^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('Total fault current = %9.4f per unit\\n\\n', Ifabcm(2)) fprintf('Bus Voltages during the fault in per unit \\n\\n') fprintf(' Bus -------Voltage Magnitude------- \\n') fprintf(' No. Phase a Phase b Phase c \\n')
for n = 1:nbus Vf0(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(' .4f', abs(Va(n))),fprintf(' .4f', abs(Vb(n))) fprintf(' .4f\\n', abs(Vc(n))) end
fprintf(' \\n')
fprintf('Line currents for fault at bus No. %g\\n\\n', nf)
fprintf(' From To -----Line Current Magnitude---- \\n') fprintf(' Bus Bus Phase a Phase b Phase c \\n')
for n= 1:nbus for I = 1:nbr
if nl(I) == n | nr(I) == n if nl(I) ==n k = nr(I); elseif nr(I) == n k = nl(I); end if k ~= 0 Ink0(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); if real(Inkabc(2)) < 0
fprintf('%7g', n), fprintf('g', k),
fprintf(' .4f', abs(Inkabc(1))),fprintf(' .4f', abs(Inkabc(2)))
fprintf(' .4f\\n', abs(Inkabc(3)))
elseif real(Inkabc(2)) ==0 & imag(Inkabc(2)) > 0 fprintf('%7g', n), fprintf('g', k),
fprintf(' .4f', abs(Inkabc(1))),fprintf(' .4f', abs(Inkabc(2))) fprintf(' .4f\\n', abs(Inkabc(3))) else, end else, end else, end end if n==nf
fprintf('%7g',n), fprintf(' F'),
fprintf(' .4f', Ifabcm(1)),fprintf(' .4f', Ifabcm(2)) fprintf(' .4f\\n', Ifabcm(3)) else, end end resp=0;
while strcmp(resp, 'n')~=1 & strcmp(resp, 'N')~=1 & strcmp(resp, 'y')~=1 & strcmp(resp, 'Y')~=1
resp = input('Another fault location? Enter ''y'' or ''n'' within single quote -> ');
if strcmp(resp, 'n')~=1 & strcmp(resp, 'N')~=1 & strcmp(resp, 'y')~=1 & strcmp(resp, 'Y')~=1
fprintf('\\n Incorrect reply, try again \\n\\n'), end end
if resp == 'y' | resp == 'Y' nf = 999; else ff = 0; end end
（3）dlgfault.m程序代码：
% The program dlgfault is designed for the double line-to-ground % fault analysis of a power system network. The program requires % the positive-, negative- or zero-sequence bus impedance matrices, % Zbus1 Zbus2,and Zbus0. The bus impedances matrices may be defined % by the user, obtained by the inversion of Ybus or it may be % determined either from the function Zbus = zbuild(zdata) % or the function Zbus = zbuildpi(linedata, gendata, yload). % The program prompts the user to enter the faulted bus number % and the fault impedance Zf. The prefault bus voltages are % defined by the reserved Vector V. The array V may be defined or % it is returned from the power flow programs lfgauss, lfnewton, % decouple or perturb. If V does not exist the prefault bus voltages
