FORMATION OF YBUS BY INSPECTION METHOD
AIM: Develop a MATLAB programme to obtain bus admittance matrix of a given network by
Inspection technique.
DATA GIVEN:
1 3 4
Z13 Z34
Line 2 Line 6
e 3
Z12 Lin
Line 1
Line 7
Z23 4
Line Z45
Z24
2 Line 5 5
Z25
1. 5-Bus network with 7-lines: ( from stagg)
Line No Bus Codes (p-q) Line impedance(z) Half line charging
admittance y’pq/2
1 1-2 0.02+j0.06 j0.03
2 1-3 0.08+j0.24 j0.025
3 2-3 0.06+j0.18 j0.02
4 2-4 0.06+j0.18 j0.02
5 2-5 0.04+j0.12 j0.015
6 3-4 0.01+j0.03 j0.01
7 4-5 0.08+j0.24 j0.025
Theory:
PROCEDURE:
1. Develop the algorithm for inspection technique to form YBUS of a given network given in
data1.
2. Write the program in Mat lab and execute it. Print the result.
3. Execute the same program for data 2 and print YBUS.
Formation of YBUS by inspection method (without tap changing transformers)
Algorithm:-
(1) Declare the variables.
(2) Read the number of buses and lines.
(3) Read from bus number (fb), To bus number (tb), R, X and Ych for each line.
(4) Initialize YBUS with zeros.
(5) Find series admittance of all the lines by inverting line impedance.
For (i=1; i<=e; i++)
yse[i] =1/complex(R[i]; X[i])
(6) For (i=1; i<=e; i++)
{
Sum=yse[i] + ych[i];
m=fb[i];
n=tb[i];
YBUS[m] [m] =YBUS[m] [m] +sum;
YBUS[n] [n] =YBUS[n] [n] +sum;
YBUS[m] [n] =-Yse[i];
YBUS[n][m]=YBUS[m][n];
}
(7) Print YBUS.
Data: - Stagg P.no: 284 5 bus network.
Programme for Formation of YBUS by Inspection Method without tap changing transformers
Programme:
%YBUS formation USING INSPECTION METHOD without tap changing transformers
ldata = [ 1 1 2 0.02+0.06i 0.03i
2 1 3 0.08+0.24i 0.025i
3 2 3 0.06+0.18i 0.02i
4 2 4 0.06+0.18i 0.02i
5 2 5 0.04+0.12i 0.015i
6 3 4 0.01+0.03i 0.01i
7 4 5 0.08+0.24i 0.025i];
lno = ldata (:, 1)
fb = ldata (:, 2)
tb = ldata (: , 3)
z = ldata (:, 4)
ych = ldata(:, 5)
ln =length(lno);
n=max (max (fb), max (tb));
y=1. /z;
ybus = zeros (n, n);
for i =1: ln
p=fb (i);
q=tb (i);
ybus (p, p) =ybus (p, p) +y (i) +ych (i);
ybus (q, q) =ybus (q, q) +y (i) +ych (i);
ybus (p, q) = -y (i);
ybus (q,p)=-y(i);
end
disp (‘YBUS OF GIVE SYSTEM IS :’);
disp (ybus);
RESULT:
YBUS of given power system network is obtained from inspection technique.
y bus of a given system is=
[6.2500 -18.6950i -5.0000 +15.0000i -1.2500 + 3.7500i 0 0
-5.0000 +15.0000i 10.8333 -32.4150i -1.6667 + 5.0000i -1.6667 + 5.0000i -2.5000 + 7.5000i
-1.2500 + 3.7500i -1.6667 + 5.0000i 12.9167 -38.6950i -10.0000 +30.0000i 0
0 -1.6667 + 5.0000i -10.0000 +30.0000i 12.9167 -38.6950i -1.2500 + 3.7500i
0 -2.5000 + 7.5000i 0 -1.2500 + 3.7500i 3.7500 -11.2100i]
DISCUSSIONS:
1. What is a primitive network?
2. What is element bus incidence matrix?
3. What are different techniques to form YBUS?
4. List out the advantages and drawbacks of inspection technique in formation of YBUS.
5. Why tap changing transformers are connected in power system network?
6. What are the advantages of and draw backs of inspection technique in forming bus
admittance matrix?
