3.0 Write a function Z = znbus (z) for the formation of the bus impedance matrix.
4.0 z is the line input and contains three columns. The first two columns are the line bus numbers
and the remaining columns contain the line resistance in per-unit. 5.0 The function should return the bus impedance matrix.
4. Exercises
Use the written function, Z = znbus(z) to obtain the Ybus of the following power system network: Example 1
Figure 3: One-line diagram of power system
For example ,from the textbook “power system analysis” No.2 edition 3 on page 61~62 Table 1：Transformer and transmissssion Line data From Bus# 1 1 To Bus# 2 3 R(p.u) 0.1 0 X(p.u) 0.4 0.3 B(p.u)or ratio K j0.01528 1.1 Others 7
Experiment 2 Bus Impedance Matrix
1 2 4 4 0.12 0.08 0.5 0.40 j0.01920 J0.01413 Q2. You are required to write the Zbus into a text file. (Hint: use the matlab text compiler)
Example 2
For the system shown, form Zbus matrix using the building algorithm
Solution
A line list
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Apply Kron reduction to eliminate the last row
Hint. You are required to compile a program to form the Zbus Matrix.the following program is a
reference program to you.
The program is:
%function OutPut=The_Node_impedance_Matrix(handles) %is a subroutine of PowerSystemCalculation
function OutPut=The_Node_impedance_Matrix(handles)
%the following program is open a data file and get the Number of % Node and Branch data to form a nodal impedance matrix
%the following code is open a file and read the data of power system network [fname,pname] = uigetfile('*.dbf','Select the network parametre data-file'); Topo_Structure_And_Branch_Para= csvread(fname);
%get the electric power system the number of branch and the parametre of % elements
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Experiment 2 Bus Impedance Matrix
[NumberOfBranch,NumberOfPara]=size(Topo_Structure_And_Branch_Para); %Temporary1---temporary variable 1 %Temporary2---temporary variable 2
Temporary1=max(Topo_Structure_And_Branch_Para(:,1)); Temporary2=max(Topo_Structure_And_Branch_Para(:,2)); if Temporary1 > Temporary2
NumberOfNode=Temporary1; else
NumberOfNode=Temporary2; end
% The following program is to form the Nodal impedance Matrix % and the Topologic structure and Branch Parametres are arranged
% I,J,R,X,C/K, and pay attention to the inpedence of transformer is in the % side of Node J and the ratio of transformer 1:K is in the side of Node % % set the initial value of Nodal Admittance Matrix to zero for CircleNumber1=1:NumberOfNode
for CircleNumber2=1:NumberOfNode
Nodal_impedance_Matrix(CircleNumber1,CircleNumber2)=0; end end
for CircleNumber=1:NumberOfBranch
if Topo_Structure_And_Branch_Para(CircleNumber,5) > 0.85
Nodal_impedance_Matrix(Topo_Structure_And_Branch_Para(Topo_Structure_And_Branch_Para(CircleNumber,1),Topo_Structure_And_Branch_Para(CircleNumber,1)))=...
Nodal_impedance_Matrix(Topo_Structure_And_Branch_Para(Topo_Structure_And_Branch_Para(CircleNumber,1),Topo_Structure_And_Branch_Para(CircleNumber,1)))+Topo_Structure_And_Branch_Para(CircleNumber,5)^2/(Topo_Structure_And_Branch_Para(CircleNumber,3)+... j*Topo_Structure_And_Branch_Para(CircleNumber,4)) ;
Nodal_impedance_Matrix(Topo_Structure_And_Branch_Para(CircleNumber,2),Topo_Structure_And_Branch_Para(CircleNumber,2))=...
Nodal_impedance_Matrix(Topo_Structure_And_Branch_Para(CircleNumber,2),Topo_Structure_And_Branch_Para(CircleNumber,2))+...
1/((Topo_Structure_And_Branch_Para(CircleNumber,3)+j*Topo_Structure_And_Branch_Para(CircleNumber,4)));
Nodal_impedance_Matrix(Topo_Structure_And_Branch_Para(CircleNumber,1),Topo_Structure_And_Branch_Para(CircleNumber,2))=...
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Nodal_impedance_Matrix(Topo_Structure_And_Branch_Para(CircleNumber,1),Topo_Structure_And_Branch_Para(CircleNumber,2))...
-Topo_Structure_And_Branch_Para(CircleNumber,5)/...
((Topo_Structure_And_Branch_Para(CircleNumber,3)+j*Topo_Structure_And_Branch_Para(CircleNumber,4)));
Nodal_impedance_Matrix(Topo_Structure_And_Branch_Para(CircleNumber,2),Topo_Structure_And_Branch_Para(CircleNumber,1))=...
Nodal_impedance_Matrix(Topo_Structure_And_Branch_Para(CircleNumber,1),Topo_Structure_And_Branch_Para(CircleNumber,2)); else
Nodal_impedance_Matrix(Topo_Structure_And_Branch_Para(CircleNumber,1),Topo_Structure_And_Branch_Para(CircleNumber,1))=...
Nodal_impedance_Matrix(Topo_Structure_And_Branch_Para(CircleNumber,1),Topo_Structure_And_Branch_Para(CircleNumber,1))+...
+1/(Topo_Structure_And_Branch_Para(CircleNumber,3)+...
j*Topo_Structure_And_Branch_Para(CircleNumber,4))+j*Topo_Structure_And_Branch_Para(CircleNumber,5);
Nodal_impedance_Matrix(Topo_Structure_And_Branch_Para(CircleNumber,2),Topo_Structure_And_Branch_Para(CircleNumber,2))=...
Nodal_impedance_Matrix(Topo_Structure_And_Branch_Para(CircleNumber,2),Topo_Structure_And_Branch_Para(CircleNumber,2))+...
+1/(Topo_Structure_And_Branch_Para(CircleNumber,3)+...
j*Topo_Structure_And_Branch_Para(CircleNumber,4))+j*Topo_Structure_And_Branch_Para(CircleNumber,5)
Nodal_impedance_Matrix(Topo_Structure_And_Branch_Para(CircleNumber,1),Topo_Structure_And_Branch_Para( CircleNumber,2))=...
Nodal_impedance_Matrix(Topo_Structure_And_Branch_Para(CircleNumber,1),Topo_Structure_And_Branch_Para( CircleNumber,2))...
-1/(Topo_Structure_And_Branch_Para(CircleNumber,3)+...
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