Hi friends, I have a question about the covariance matrix in 'State_est' function. Below is the sigma which is used in Matpower.
sigma = [ 0.02 * abs(Sf) + 0.0052 * fullscale * ones(nbr,1); 0.02 * abs(St) + 0.0052 * fullscale * ones(nbr,1); 0.02 * abs(Sbus) + 0.0052 * fullscale * ones(nb,1); 0.2 * pi/180 * 3*ones(nb,1); 0.02 * abs(Sf) + 0.0052 * fullscale * ones(nbr,1); 0.02 * abs(St) + 0.0052 * fullscale * ones(nbr,1); 0.02 * abs(Sbus) + 0.0052 * fullscale * ones(nb,1); 0.02 * abs(V0) + 0.0052 * 1.1 * ones(nb,1); ] ./ 3; We have a large difference in the value of active and reactive power flow, namely in line 2-3, active and reactive power flow is 73.69 and 3.51 respectively. So, Instead of using 'abs(Sf)' for both active and reactive entry in covariance matrix, can I use abs(P_flow_flf) for active power and abs(Q_flow_flf) for reactive power noise. So, sigma changes to: Pflf=branch(:,PF); % power flow result Ptlf=branch(:,PT); Qflf=branch(:,QF); Qtlf=branch(:,QT); P_flow_flf = Pflf./baseMVA; P_flow_tlf = Ptlf./baseMVA; Q_flow_flf = Qflf./baseMVA; Q_flow_tlf = Qtlf./baseMVA; Sbus_lf = V .* conj(Ybus * V); sigma_New = [ 0.02 * abs(P_flow_flf) + 0.0052 * fullscale * ones(nbr,1); 0.02 * abs(P_flow_tlf) + 0.0052 * fullscale * ones(nbr,1); 0.02 * abs(real(Sbus_lf)) + 0.0052 * fullscale * ones(nb,1); 0.2 * pi/180 * 3*ones(nb,1); 0.02 * abs(Q_flow_flf) + 0.0052 * fullscale * ones(nbr,1); 0.02 * abs(Q_flow_tlf) + 0.0052 * fullscale * ones(nbr,1); 0.02 * abs(imag(Sbus_lf)) + 0.0052 * fullscale * ones(nb,1); 0.02 * abs(V0) + 0.0052 * 1.1 * ones(nb,1); ] ./ 3; Thank you, Naime So, is it correct to use I m When I checked the active power flow in
