短路电流计算 _电力系统_短路计算_

% 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 % are automatically set to 1.0 per unit. The program obtains the % total fault current, bus voltages and line currents during the fault. function dlgfault(zdata0, Zbus0, 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); 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); for k = 1:nbr0 if R0(k) == inf | X0(k) == inf R0(k) = 99999999; X0(k) = 999999999; else, end end ZB1 = R1 + j*X1; ZB0 = R0 + j*X0; ZB2 = R2 + j*X2; if exist('V') == 1 if length(V) == nbus V0 = V; else, end else, V0 = ones(nbus, 1) + j*zeros(nbus, 1); end fprintf('\nDouble line-to-ground 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('Double line-to-ground 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]; 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('Total fault current = %9.4f per unit\n\n', Iftm) 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 - 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(' %11.4f', abs(Va(n))),fprintf(' %11.4f', abs(Vb(n))) fprintf(' %11.4f\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 Ink1(n, k) = (Vf1(n) - Vf1(k))/ZB1(I); Ink2(n, k) = (Vf2(n) - Vf2(k))/ZB2(I); else, end else, end end for I = 1:nbr0 if nl0(I) == n | nr0(I) == n if nl0(I) ==n k = nr0(I); elseif nr0(I) == n k = nl0(I); end if k ~= 0 Ink0(n, k) = (Vf0(n) - Vf0(k))/ZB0(I); else, end else, end end 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 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('%10g', k), fprintf(' %11.4f', abs(Inkabc(1))),fprintf(' %11.4f', abs(Inkabc(2))) fprintf(' %11.4f\n', abs(Inkabc(3))) elseif real(Inkabc(2)) ==0 & imag(Inkabc(2)) > 0 fprintf('%7g', n), fprintf('%10g', k), fprintf(' %11.4f', abs(Inkabc(1))),fprintf(' %11.4f', abs(Inkabc(2))) fprintf(' %11.4f\n', abs(Inkabc(3))) else, end else, end else, end end if n==nf fprintf('%7g',n), fprintf(' F'), fprintf(' %11.4f', Ifabcm(1)),fprintf(' %11.4f', Ifabcm(2)) fprintf(' %11.4f\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