l_crit.m

用MATLAB编的配电网自动化的一些程序

function [y,U]=L_crit(U,shineng)
%sym l z_1 z_2 z_0 zs_1 zs_2 zs_0 zs z
syms zs zf_1 zf_2 zf_0 l zs_1 zs_2 zs_0 U_sag
zs1=0.663;z_1=0.278;z_2=0.278;z_0=1.478;zs2=0.663;
switch shineng
    
case 1,
U=subs(U,{zs,zf_1,zf_2,zf_0},{zs1,symmul(z_1,l),symmul(z_2,l),symmul(z_0,l)});
case 2,
    
U=subs(U,{zs_1,zf_1},{zs2,symmul(z_1,l)})
%U1=numeric(U)
%U=abs(U)
case 3,
    U=subs(U,{zs_0,zs_1,zf_1,zf_2,zf_0},{zs1,zs1,symmul(z_1,l),symmul(z_2,l),symmul(z_0,l)});
end


y=solve(U_sag-U,l)