5节点牛顿法.m

该程序用matlab语言编写的计算机潮流计算程序。

%本程序的功能是用牛顿-拉夫逊法进行潮流计算
n=input('输入节点数:n=');
nl=input('输入支路数:nl=');
isb=input('输入平衡母线节点号:isb=');
pr=input('输入误差精度:pr=');
B1=input('输入由支路参数形成的矩阵:B1=');
B2=input('输入各节点参数形成的矩阵:B2=');
X=input('输入由节点号及其对地阻抗形成的矩阵:X=');
Y=zeros(n);e=zeros(1,n);f=zeros(1,n);V=zeros(1,n);O=zeros(1,n);S1=zeros(nl);
for i=1:n
    if X(i,2)~=0;
        p=X(i,1);
        Y(p,p)=1./X(i,2);
    end
end
for i=1:nl
    if B1(i,6)==0
        p=B1(i,1);q=B1(i,2);
    else p=B1(i,2);q=B1(i,1);
    end
   Y(p,q)=Y(p,q)-1./(B1(i,3)*B1(i,5));
   Y(q,p)=Y(p,q);
   Y(q,q)=Y(q,q)+1./(B1(i,3)*B1(i,5)^2)+B1(i,4)./2;
   Y(p,p)=Y(p,p)+1./B1(i,3)+B1(i,4)./2;
end        %求导纳矩阵
G=real(Y); B=imag(Y);
for i=1:n
    e(i)=real(B2(i,3));
    f(i)=imag(B2(i,3));
    V(i)=B2(i,4);
end
for i=1:n
    S(i)=B2(i,1)-B2(i,2);
    B(i,i)=B(i,i)+B2(i,5);
end
P=real(S);Q=imag(S);
ICT1=0;IT2=1;N0=2*n;N=N0+1;a=0;
while IT2~=0
    IT2=0;a=a+1;
    for i=1:n
        if i~=isb
            C(i)=0;
            D(i)=0;
            for j1=1:n
                C(i)=C(i)+G(i,j1)*e(j1)-B(i,j1)*f(j1);
                D(i)=D(i)+G(i,j1)*f(j1)+B(i,j1)*e(j1);
            end
            P1=C(i)*e(i)+f(i)*D(i);
            Q1=f(i)*C(i)-D(i)*e(i);        %求'P,Q'
            V2=e(i)^2+f(i)^2;
            if B2(i,6)~=2
                DP=P(i)-P1;
                DQ=Q(i)-Q1;
                for j1=1:n
                    if j1~=isb & j1~=i
                        X1=-G(i,j1)*e(i)-B(i,j1)*f(i);
                        X2=B(i,j1)*e(i)-G(i,j1)*f(i);
                        X3=X2;
                        X4=-X1;
                        p=2*i-1; q=2*j1-1; J(p,q)=X3; J(p,N)=DQ; m=p+1;
                        J(m,q)=X1; J(m,N)=DP; q=q+1; J(p,q)=X4; J(m,q)=X2;
                    elseif j1==i & j1~=isb
                            X1=-C(i)-G(i,i)*e(i)-B(i,i)*f(i);
                            X2=-D(i)+B(i,i)*e(i)-G(i,i)*f(i);
                            X3=D(i)+B(i,i)*e(i)-G(i,i)*f(i);
                            X4=-C(i)+G(i,i)*e(i)+B(i,i)*f(i);
                            p=2*i-1; q=2*j1-1; J(p,q)=X3; J(p,N)=DQ; m=p+1;
                            J(m,q)=X1; J(m,N)=DP; q=q+1; J(p,q)=X4; J(m,q)=X2;
                        end
                    end
                else
                    DP=P(i)-P1;
                    DV=V(i)^2-V2;
                    for j1=1:n
                        if j1~=isb & j1~=i
                            X1=-G(i,j1)*e(i)-B(i,j1)*f(i);
                            X2=B(i,j1)*e(i)-G(i,j1)*f(i);
                            X5=0;
                            X6=0;
                            p=2*i-1; q=2*j1-1; J(p,q)=X5; J(p,N)=DV; m=p+1;
                            J(m,q)=X1; J(m,N)=DP; q=q+1; J(p,q)=X6; J(m,q)=X2;
                        elseif j1==i & j1~=isb
                            X1=-C(i)-G(i,i)*e(i)-B(i,i)*f(i);
                            X2=-D(i)+B(i,i)*e(i)-G(i,i)*f(i);
                            X5=-2*e(i);
                            X6=-2*f(i);
                            p=2*i-1; q=2*j1-1; J(p,q)=X5; J(p,N)=DV; m=p+1;
                            J(m,q)=X1; J(m,N)=DP; q=q+1; J(p,q)=X6; J(m,q)=X2;
                        end
                    end
                end
            end
        end          
        for k=3:N0
            k1=k+1; N1=N;
            for k2=k1:N1
                J(k,k2)=J(k,k2)./J(k,k);
            end
            J(k,k)=1;
            if k~=3
                k4=k-1;
                for k3=3:k4
                    for k2=k1:N1
                        J(k3,k2)=J(k3,k2)-J(k3,k)*J(k,k2);
                    end
                    J(k3,k)=0;
                end
                if k==N0, break; end
                for k3=k1:N0
                    for k2=k1:N1
                        J(k3,k2)=J(k3,k2)-J(k3,k)*J(k,k2);
                    end
                    J(k3,k)=0;
                end
            else 
                for k3=k1:N0
                    for k2=k1:N1
                        J(k3,k2)=J(k3,k2)-J(k3,k)*J(k,k2);
                    end
                    J(k3,k)=0;
                end
            end
        end
        for k=3:2:N0-1
            L=(k+1)./2;
            e(L)=e(L)-J(k,N);
            k1=k+1;
            f(L)=f(L)-J(k1,N);
        end
        for k=3:N0
            DET=abs(J(k,N));
            if DET>=pr
                IT2=IT2+1;
            end
        end
        ICT2(a)=IT2;
        ICT1=ICT1+1;
        for k=1:n
            dy(k)=sqrt(e(k)^2+f(k)^2)
        end
        for i=1:n
            Dy(ICT1,i)=dy(i);
        end
    end                         %用高斯消去法解"w=-J*V"
    disp('迭代次数');
    disp(ICT1);
    disp('没有达到精度要求的个数');
    disp(ICT2);
    for k=1:n
        V(k)=sqrt(e(k)^2+f(k)^2);
        O(k)=atan(f(k)./e(k))*180./pi;
    end
    E=e+f*j;
    disp('各节点的实际电压标么值E为(节点号从小到大排列):');
    disp(E);
    disp('各节点的电压大小V为(节点号从小到大排列):');
    disp(V);
    disp('各节点的电压相角O为(节点号从小到大排列):');
    disp(O);
    for p=1:n
        C(p)=0;
        for q=1:n
            C(p)=C(p)+conj(Y(p,q))*conj(E(q));
        end
        S(p)=E(p)*C(p);
    end
    disp('各节点的功率S为(节点号从小到大排列):');
    disp(S);
    disp('各条支路的首端功率Si为(顺序同您输入B1时一样):');
    for i=1:nl
        if B1(i,6)==0
            p=B1(i,1); q=B1(i,2);
        else p=B1(i,2); q=B1(i,1);
        end
        Si(p,q)=E(p)*(conj(E(p))*conj(B1(i,4)./2)+(conj(E(p)*B1(i,5))-conj(E(q)))*conj(1./(B1(i,3)*B1(i,5))));
        disp(Si(p,q));
    end
    disp('各条支路的末端功率Si为(顺序同您输入B1时一样);');
    for i=1:nl
        if B1(i,6)==0
            p=B1(i,1); q=B1(i,2);
        else p=B1(i,2); q=B1(i,1);
        end
        Sj(q,p)=E(q)*(conj(E(q))*conj(B1(i,4)./2)+(conj(E(q)./B1(i,5))-conj(E(p)))*conj(1./(B1(i,3)*B1(i,5))));
        disp(Sj(q,p));
    end
    disp('各条支路的功率损耗DS为(顺序同您输入B1时一样):');
    for i=1:nl
        if B1(i,6)==0
            p=B1(i,1); q=B1(i,2);
        else p=B1(i,2); q=B1(i,1);
        end
        DS(i)=Si(p,q)+Sj(q,p);
        disp(DS(i));
    end 
    for i=1:ICT1
        Cs(i)=i;
    end 
    disp('以下是每次迭代后各节点的电压值(如图所示)');
    plot(Cs,Dy), xlabel('迭代次数'), ylabel('电压'), title('电压迭代次数曲线');