% Program for Bus Power Injections, Line & Power flows (p.u)...
function [Pi Qi Pg Qg Pl Ql] = loadflow(nb,V,del,BMva)
Y = ybusppg(nb); % Calling Ybus program..
lined = linedatas(nb); % Get linedats..
busd = busdatas(nb); % Get busdatas..
Vm = pol2rect(V,del); % Converting polar to rectangular..
Del = 180/pi*del; % Bus Voltage Angles in Degree...
fb = lined(:,1); % From bus number...
tb = lined(:,2); % To bus number...
nl = length(fb); % No. of Branches..
Pl = busd(:,7); % PLi..
Ql = busd(:,8); % QLi..
Iij = zeros(nb,nb);
Sij = zeros(nb,nb);
Si = zeros(nb,1);
% Bus Current Injections..
I = Y*Vm;
Im = abs(I);
Ia = angle(I);
%Line Current Flows..
for m = 1:nl
p = fb(m); q = tb(m);
Iij(p,q) = -(Vm(p) - Vm(q))*Y(p,q); % Y(m,n) = -y(m,n)..
Iij(q,p) = -Iij(p,q);
end
Iij = sparse(Iij);
Iijm = abs(Iij);
Iija = angle(Iij);
% Line Power Flows..
for m = 1:nb
for n = 1:nb
if m ~= n
Sij(m,n) = Vm(m)*conj(Iij(m,n))*BMva;
end
end
end
Sij = sparse(Sij);
Pij = real(Sij);
Qij = imag(Sij);
% Line Losses..
Lij = zeros(nl,1);
for m = 1:nl
p = fb(m); q = tb(m);
Lij(m) = Sij(p,q) + Sij(q,p);
end
Lpij = real(Lij);
Lqij = imag(Lij);
% Bus Power Injections..
for i = 1:nb
for k = 1:nb
Si(i) = Si(i) + conj(Vm(i))* Vm(k)*Y(i,k)*BMva;
end
end
Pi = real(Si);
Qi = -imag(Si);
Pg = Pi+Pl;
Qg = Qi+Ql;
disp('#########################################################################################');
disp('-----------------------------------------------------------------------------------------');
disp(' Newton Raphson Loadflow Analysis ');
disp('-----------------------------------------------------------------------------------------');
disp('| Bus | V | Angle | Injection | Generation | Load |');
disp('| No | pu | Degree | MW | MVar | MW | Mvar | MW | MVar | ');
for m = 1:nb
disp('-----------------------------------------------------------------------------------------');
fprintf('%3g', m); fprintf(' %8.4f', V(m)); fprintf(' %8.4f', Del(m));
fprintf(' %8.3f', Pi(m)); fprintf(' %8.3f', Qi(m));
fprintf(' %8.3f', Pg(m)); fprintf(' %8.3f', Qg(m));
fprintf(' %8.3f', Pl(m)); fprintf(' %8.3f', Ql(m)); fprintf('\n');
end
disp('-----------------------------------------------------------------------------------------');
fprintf(' Total ');fprintf(' %8.3f', sum(Pi)); fprintf(' %8.3f', sum(Qi));
fprintf(' %8.3f', sum(Pi+Pl)); fprintf(' %8.3f', sum(Qi+Ql));
fprintf(' %8.3f', sum(Pl)); fprintf(' %8.3f', sum(Ql)); fprintf('\n');
disp('-----------------------------------------------------------------------------------------');
disp('#########################################################################################');
disp('-------------------------------------------------------------------------------------');
disp(' Line FLow and Losses ');
disp('-------------------------------------------------------------------------------------');
disp('|From|To | P | Q | From| To | P | Q | Line Loss |');
disp('|Bus |Bus| MW | MVar | Bus | Bus| MW | MVar | MW | MVar |');
for m = 1:nl
p = fb(m); q = tb(m);
disp('-------------------------------------------------------------------------------------');
fprintf('%4g', p); fprintf('%4g', q); fprintf(' %8.3f', Pij(p,q)); fprintf(' %8.3f', Qij(p,q));
fprintf(' %4g', q); fprintf('%4g', p); fprintf(' %8.3f', Pij(q,p)); fprintf(' %8.3f', Qij(q,p));
fprintf(' %8.3f', Lpij(m)); fprintf(' %8.3f', Lqij(m));
fprintf('\n');
end
disp('-------------------------------------------------------------------------------------');
fprintf(' Total Loss ');
fprintf(' %8.3f', sum(Lpij)); fprintf(' %8.3f', sum(Lqij)); fprintf('\n');
disp('-------------------------------------------------------------------------------------');
disp('#####################################################################################');
