%%
%利用镜像法计算架空线场强
%依据 韦钢 李海峰 《同杆并架多回线下方的电场强度和感应电压》 
%%
clc
clear
%电压（复数，至上到下，先左后右）
%双回
Volt=[220; 220*exp(1j*240*pi/180); 220*exp(1j*120*pi/180);220; 220*exp(1j*240*pi/180); 220*exp(1j*120*pi/180) ];
%形成电位系数矩阵
H=diag([28.5, 21, 27.5, 28.5, 21, 27.5 ]);
r=diag([0.2,0.2,0.2,0.2,0.2,0.2]);
Dcomma=[0,58.5,55,62.42,58.98,55.5;
        58.5,0,51.5,58.98,55.5,52.1;
        55, 51.5 0,55.5,52.1 48.7;
        62.42,58.98,55.55,0,58.5,55;
        58.98,55.55,52.13,58.5,0,51.5;
        55.55,52.13,48.73,55,51.5,0];
D=[   0  3.51 7.02 7.2 8.27 10.4;
    3.51 0 3.51 8.27 7.8 8.8
    7.02 3.51 0 10.4 8.8 8.4
    7.2 8.27 10.48 0 3.5 7.02
    8.27 7.8 8.8 3.51 0 3.51
    10.4 8.8 8.4 7.02 3.51 0];
eslong=1;
P=1/pi/eslong*log(2*H./r);
P(isnan(P))=0;
P2=1/pi/eslong*log(Dcomma./D);
P2(isnan(P2))=0;
P=P+P2;
%求电荷
QRI=inv(P2)*Volt;
%导线坐标
ABCx=[-3.6; -3.9; -4.2; 3.6; 3.9; 4.2];
ABCy=[31; 27.5; 24; 31; 27.5; 24];
%求地面场强
plotY=zeros(60,1);
plotX=zeros(60,1);
for I=-30:30
    x=I;
    y=0;
    ERy=sum( (ABCy-y)./( (ABCy-y).^2+(ABCx-x).^2 ).*real(QRI)./2/pi/eslong );
    EIy=sum( (ABCy-y)./( (ABCy-y).^2+(ABCx-x).^2 ).*imag(QRI)./2/pi/eslong );
    
    ERx=sum( (ABCx-x)./( (ABCy-y).^2+(ABCx-x).^2 ).*real(QRI)./2/pi/eslong );
    EIx=sum( (ABCx-x)./( (ABCy-y).^2+(ABCx-x).^2 ).*imag(QRI)./2/pi/eslong );
    E=sqrt(ERy.^2+EIy.^2+ERx.^2+EIx.^2);
    plotY(I+31)=E;
    plotX(I+31)=x;
end
plot(plotX,plotY);