retail=dlmread('E:\书籍\论文\配电网状态估计\零售业负荷.txt');
retail=retail/max(retail);
tobacco=dlmread('E:\书籍\论文\配电网状态估计\烟草负荷.txt');
tobacco=tobacco/max(retail);
residential=dlmread('E:\书籍\论文\配电网状态估计\城镇居民负荷.txt');
residential=residential/max(retail);
x=1:length(retail);
subplot(2,2,1);
plot(x,retai