Hi - I am still trying to hand calculate the flow into branch 2 from bus 1 to bus 2. I can’t get my results to match MATPOWER.
I get Q into the banks from bus 1 of,
Bank #1: 24.00 MVAR
Bank #2: -25.02 MVAr
Attached is my short calculation and the .m file. Is there a way to have
MATPOWER barf out the YBUS matrix?
================================================================================
| Bus Data |
================================================================================
Bus Voltage Generation Load
# Mag(pu) Ang(deg) P (MW) Q (MVAr) P (MW) Q (MVAr)
----- ------- -------- -------- -------- -------- --------
1 1.000 0.000* 0.00 1.14 - -
2 0.976 0.000 - - - -
-------- -------- -------- --------
Total: 0.00 1.14 0.00 0.00
================================================================================
| Branch Data |
================================================================================
Brnch From To From Bus Injection To Bus Injection Loss (I^2 * Z)
# Bus Bus P (MW) Q (MVAr) P (MW) Q (MVAr) P (MW) Q (MVAr)
----- ----- ----- -------- -------- -------- -------- -------- --------
1 1 2 0.00 23.91 0.00 -23.34 -0.000 0.57
2 1 2 0.00 -22.77 0.00 23.34 -0.000 0.57
-------- --------
Total: 0.000 1.14
Best regards,
russ
function mpc = circulating
% This example is to show circulating MVAR losses in 2 parallel banks
% with different turns ratios (no load connected)
%
% 161kV Bus 1 is infinite and is 1 pu and zero degrees
% 13.8kV Bus 2 has no load connected
% Transformer 1 between bus 1 & 2 is j0.1 pu (100MVA, 161kV base) and turns
ratio matches ratio of voltage bases (1.0)
% 161kV:13.8kV
% Transformer 2 between bus 1 & 2 is j0.1 pu (100MVA, 161kV base) and turns
ratio is 1.05 of voltage base ratio
% 161kV:13.14kV (bank 1)
%
%
% The voltage difference is (13.8kV 13.14kV)/13.8kV = 0.0478 pu which is the
driving voltage for the circulating current.
% The circulating current will be 0.0478/0.2pu = 0.239pu A. This circulating
current will produce a var drop of
% Q = (0.239)(0.239) x (0.2) = 0.01144 pu. This is 1.14MVAr.
% - - - - - - - - - - -
%
\%% MATPOWER Case Format : Version 2
mpc.version = '2';
\%%----- Power Flow Data -----\%%
\%% system MVA base
mpc.baseMVA = 100;
\%% Vm under mpc.gen sets the slack bus (1) voltage magnitude
\%% Va under mpc.bus sets the slack bus (1) voltage angle
\%%
% bus_i type Pd Qd Gs Bs area Vm Va
baseKV zone Vmax Vmin
mpc.bus = [
1 3 0 0 0 0 1 1 0 161 1 1
1;
2 1 0 0 0 0 1 1 0 13.8 1 0
0;
];
\%% generator data
% bus Pg Qg Qmax Qmin Vg mBase status
Pmax Pmin Pc1 Pc2 Qc1min Qc1max Qc2min Qc2max ramp_agc
ramp_10 ramp_30 ramp_q apf ?
mpc.gen = [
1 0 0 0 0 1.0 0 1 0 0 0
0 0 0 0 0 0 0 0 0 0
0;
];
\%% branch data
% fbus tbus r x b rateA rateB rateC
ratio angle status angmin angmax
mpc.branch = [
1 2 0 .1 0 0 0 0 0 0 1
0 0;
% the second branch is via transformer that has 1.05 higher turns ratio as
compared to 161/13.8
1 2 0 .1 0 0 0 0 1.05023 0
1 0 0;
];
power.pdf
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